These spiders make a littery web and the webs can be described as an intersecting mass of scaffold work with a central area consisting of a three-dimensional trellis of silk. From the web to the ground are vertical threads with sticky glue at the bottom. If an insect crawls against the thread it will break and the prey will hang in the air awaiting the attack of the spider. Although they are small of size they are violent attackers and do not fear to attack much larger insects than themselves.
The members of this family are also called comb-footed spider because they have a "comb" on their last pair of legs. The comb is a series of serrated spines which they use to comb out the silk from the spinnerets. This combed silk is not sticky but insects get entangled in this "wool".
The dangerous black widow or red back, (Latrodectus hasselti) belongs to this family and is notorious for its poisonous neurotoxic venom.

In Australia 20 genera and 90 species of this family are described.

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Survey of 2144 cases of red-back spider bites: Australia and New Zealand, 1963--1976.

Sutherland SK, Trinca JC.

An analysis has been made of 2144 consecutive cases of latrodectism (envenomation by the red-back spider, Latrodectus mactans hasselti) reported to the Commonwealth Serum Laboratories. In the last eight years, notifications have averaged 240 cases per annum. Bites, usually on the extremities (74%), occurred most frequently in the summer months, and in the afternoon or evening. Most victims (79%) were aged between 18 and 50 years and 64.4% of them were males. Males are still often bitten on the genitals or buttocks (9.7% of cases). Local pain, redness and swelling were the most common symptoms, although significant pain was felt at other sites in 39% of the cases. The regional lymph nodes often became swollen and tender within 30 minutes. General effects included nausea, vomiting and sweating, but coma and respiratory failure were very uncommon, probably because of use of specific antivenom. This was administered within 24 hours of the bite in 92% of cases, and within two hours in 70%. Although 11 anaphylactic reactions (0.54%) were reported, no deaths resulted either from the venom or from reactions to the antivenom. Few delayed serum reactions (1.7%) were recorded. The action of the venom is described and the management of red-back spider bite is outlined.

Med J Aust. 1978 Dec 30;2(14):620-3.

A black widow's toxin is 15 times more poisonous than that of a rattlesnake, making her one of the few spiders in the world capable of seriously harming humans.
Due to the good hospital services, deaths from a bite are not recorded any more.
Her size is around 10 mm. Only in her final moult she gets her black colour. The male is creamy brown of colour and with a white hour-glass pattern on the underside of his abdomen. He is about 3 mm long.

Latrodectus builds her web in dark places near the ground, preferring the sheltered sides of buildings, abandoned rodent holes, or openings in stone outcroppings. She seldom ventures indoors, but anyone living in black widow territory should be aware that she sometimes makes a home in outbuildings such as woodsheds or outdoor toilets. The web is easily recognized by its tangled appearance, and a series of vertical trap threads extending to the ground. The web silk is extremely strong. Crawling insects getting stuck on the sticky threads are quickly lifted into the web where they're wrapped in layers of silk, injected with venom, and sucked dry. She lays 50 - 200 eggs usually in 4 or 5 egg-sacs. Females mature over a period of 4-8 month and males in a 2-3 month period. The female can live up to three years and males only 6 months. After 14 days the spiderlings emerge from the eggs. This emerging is often correlated on the onset of rain when temperatures are low and humidity high. The spider are cannibalistic and. The spider leaves the web by a process known as "ballooning". A thread line of silk is released until the drag of the air is strong enough to lift the young spider in the air.

There is a dispute whether she is a variant of the almost extinct New-Zealandic Katipo (Latrodectus mactans).

Juvenile (young) Latrodectus hasselti before her last moult where she gets her black suit with red spot(s).

Achaearanea lunata (European species) with youngsters.

Achaearanea/Theridon? ZZ011 with ant.

These spiders are closely related to Theridon spiders but their body is more elongated. They occur world-wide but most are found in tropical or sub-tropical habitats.
The spider lives in a web that is a tangle of criss-cross threads.
Often the spider can be seen guarding a white round egg sac. Several species, but only those living on the American continent, are described to be social or subsocial.

The adult spider length is between 3 - 8 mm

Argyrodes antipodianus

Argyrodes occurs world-wide.
Most species are small. Their size varies between 3 and 12 mm for the largest ones.
Males are slightly smaller than females.
Most Argyrodes species are black with silvery markings.
All are known to spin tiny webs of their own but they are more found in the webs of other spiders.
While hanging in these webs with their legs closely drawn to their body, they resemble debris, like twigs, straws, scales, bits of leave, and are so camouflaged that they are completely lost.
Largely immune to attack from their hosts because they are so small in size compared to the hosts target prey.
Argyrodes feed on the tiny insects disregarded by the host.

Episinus is found worldwide.

This spider does not look like a Theridiid spider with its long and slender appearance.
Their size is approximately 5 mm and the spider can be found at ground level between low vegetation.

Male and female are similar in appearance except for the male's slimmer abdomen. Courtship takes place in summer and is brief. The egg-sac is white and spherical and has coarse loop of silk around it.

These spiders make a very simple H or Y-shaped web near ground level. The sticky ends of the threads are attached to the ground and plants above the spider and are held by the spider. Individuals can also be found on a single horizontal line.

Female adult 23110
Undescribed not uncommon Theriid from the subfamily Hadrotarsinae.
It feeds on ants. QLD

Steatoda is a common house spider that can live for several (upto six) years.
The spider is not known to be harmfull to people.
These spiders have a robust appearance. They often have a narrow light band in front of their abdomen. The sexes are similar in appearance. The webs are generally of the Therriid design, a messy web with criss-cross threads.

These spider are very similar in shape and behaviour with Achaearanea.
They build a conical retreat of twigs and leaves in their three-dimensional contructed labyrinth web.
The pear-shaped papery looking egg-sac and the youngsters are protected in this retreat guarded by the female.
Yongsters are fed by mouth by their mother until their first hatch. After their first change of skin they feed on prey catched by their mother.

Phoroncidia are small spiders with a size around 3 mm occuring in QLD, NSW, VIC and WA.

Colours of the marbled abdomen are white, black, orange and brown.
The spider hunts at night in a simple web.
In the picture above a single thread with sticky droplets can be observed.

The egg-sac is a brownpapery sphere.

Spiders of this genus occur in the tropics.

Their size varies between 1 - 3.5 mm.

Theridula are frequently found on the underside of leaves, on bushes or in tall grass. Theridula has a web with long viscid lines that help capture flying prey. With their threads they bend leaves under which they live, mate, guard their egss and raise their youngsters.