Family: Uloboridae
Genus : Miagrammopes

Miagrammopes sp TBL Male
Miagrammopes sp TBL
Male 7mm
14-7-2015 TBL

Ventral View of a male Miagrammopes of Borneo.

Calamistrum -  is a row of specialized leg bristles used to comb out fine bands of silk. It is through the combined action of the cribellum and calamistrum that the bluish silk characteristic of the Uloborids is produced. The calamistrum is found on the upper margin of the metatarsus of the hind legs. Each bristle of the calamistrum is serrated on one side and smooth on the other.

Cribellum - is a flat plate like silk spinning organ. The cribellum consists of one or more plates covered with thousands of tiny spigots. Cribellum produce a band of fine silks.  This Cribellate silk (hackled silk) is feathery and rather fuzzy.

Spinneret -  is a cone shaped silk-spinning organ. Spinnerets produce a single silk thread.

Close-up of four spinnerets, plus at the top, the cribellum. The cribellum is an additional silk producing organ of the crebulate spiders.

The presence or absence of a cribellum is used to classify araneomorph spiders into 2 categories:
1- the cribellate spiders
2- ecribellate (not cribellate) spiders

The distinction between presence and absence of cribellum is used to study evolutionary relationships.

More about Cribellate Spiders and Ecribellate Spiders.

The first pair of legs are very much larger and longer than the others.

When this spider is at rest, all pairs of legs are pressed together or against the sides of the spider.

The very thin and long body with first pair of legs extended forwards are characteristic of this genus.



A distinctive brush on the underside of  the first pair of legs but this is not a scopula or claw tuft as is found on some other spiders.

The front legs of the Uloborids are long, often longer than the entire length of the body.



Spiders of the genus Miagrammopes have a very flat carapace

Four Eyes Spider

Diagnostically important feature of this Miagrammopes species is the presence of only a single row of 4 eyes running across the front of the spider.

Some said the other first row may be poorly developed, thus giving the impression that they have only four eyes.

Uloboridae is the only spider family without venom. The Miagrammopinae are found mostly in well-forested areas and have only 4 eyes.

Miagrammopes species does not build a web. They suspended on a single strand of silk and match itself in colour with the grass and twig  making it difficult to see.

This spider has an unusual way of catching insects. They do not spin orb-webs. Instead, they build a single-line snare which is fastened to a twig on one end and held taut by the first pair of legs at the other end. When an insect lands and hits the thread, the spider releases the line which springs back and entangles the insect.

They are usually very small, widespread, diverse and common, especially around houses, but they can also be amongst the most numerous spiders in foliage, where they spin small orb webs. They have air sensitive hairs, a silk producing plate and a calamistrum, which is a comb for reefing out this silk. 

The family Uloboridae is sub divided in two subfamilies:

1- Subfamily Uloborinae : build messy webs.
2- Subfamily Miagrammopinae : whose webs are reduced to a single strand.

These are cribellate spiders, meaning they have a cribellum to produce woolly silk which they comb out with the help of the calimustrum.

Calamistrum is a row of specialized leg bristles used to comb out fine bands of silk. It is only found on cribellate spiders that possess the spinning organ cribellum, not spinnerate

Cribellum is a silk spinning organ found in certain spiders. Unlike normal spinnerets, the cribellum consists of one or more plates covered in thousands of tiny spigots.

The calamistrum and cribellum are used to form the hackled bands of silk which are characteristic of the webs of these spiders.



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