THE CR1BELLATE SPIDERS 145 



symmetries. During the summer white, lens-shaped egg sacs are 

 hung in the deeper parts of the tangle, and after the young hatch 

 they spend some time in the web with the mother. 



Much more brightly colored than either of the above-mentioned 

 species is Dictyna sublata, often light brown in color with its oval 

 abdomen marked in yellow above, and its legs almost white. Sub- 

 lata hides its web in the leaves of bushes instead of placing it in 

 the sun. It will find a leaf with slightly rolled edges, then spin a 

 thin, sheetlike web across the opening to form a shallow bowl; in 

 this it remains and here its egg sacs are placed. 



The villagers of certain mountainous portions of Michoacan, 

 Mexico, are plagued during the rainy season by immense swarms 

 of flies that invade their homes. Their defense against these pests 

 is unique. They rely upon the mosquero (Coenothele gregalis), a 

 tiny cribellate spider one sixth of an inch long, which lives in vast 

 colonies on the twisted oaks and scrub trees at altitudes of about 

 eight thousand feet. The nest of a mosquero community is often 

 more than six feet square, and thickly invests each branch of an 

 entire tree with a spongy inner layer of dry silken lines and an 

 outer envelope of sticky hackled-band threads. The villagers cut 

 a branch from the tree, and suspend the animated fly trap from the 

 ceilings of their homes. The accommodating houseflies alight on the 

 sticky threads, whereupon they are enveloped and dragged into the 

 inner galleries to become the prey of the colony. After the fly 

 season is over and the spiders have become mature, the adults desert 

 the colonial web, perhaps to start new colonies elsewhere. Their 

 eggs and young remain, develop in the inherited nest, and are on 

 hand during the next fly season. In the field the webs of the mos- 

 quero resemble those of processionary caterpillars. 



In the inner recesses of the communal web live many small 

 beetles of the genus Melanopthalma said to attend to the cleanliness 

 of the nest by keeping it free of debris. These commensals live on 

 the small bits of food discarded by the mosquero. Also living in 

 complete harmony with the colony is one of the running spiders, 

 Poecilochroa convictrix, which is also supposed to be a commensal 

 though its exact status is less certain. 



The presence of thick brushes of scopular hairs beneath the 

 metatarsi and tarsi of the cribellates of the family Zoropsidae, and 

 the absence or great reduction in size of the median claw, would 

 seem to indicate that these spiders are hunters. Indeed, they are 

 often compared to the hunting clubionids, which they resemble in 



