Malacosoma incurvum aztecum
(Lasiocampidae)
 

This tent caterpillar is widely distributed throughout Mexico.  Like temperate zone species, it feeds on host trees when they are in the early stages of leaf development. Filip and Dirzo reported that in the Federal District, larvae are present in the field beginning in February for about 2 months.  Pupation last approxiately 18 days and  the adults oviposit soon thereafter. Egg masses remain on the branches of the trees until the larvae eclose in February of the following year.   Colonies that were observed in the field in an area north of Tepic, Mexico by Costa, Fitzgerald, and Pescador-Rubio in early January of 2003 were in all stages of development, from newly hatched caterpillars to fully grown caterpillars dispersing over the ground in search of pupation sites. The foraging behavior of the caterpillar is largely unstudied.
 
 

The tents formed by colonies hang from the branches, enclose leaves, are bag-like, and lack the layered, airy structure of the tents of americanum and californicum.

The egg mass of aztecum is similiar to that of other species of Malacosoma and covered with spumaline.  The holes in the egg mass pictured here are formed when the caterpillars (visible at the top of the egg mass) chew their way out of the eggs.

Filip, V., and R. Dirzo. 1985. Life cycle of Malacosoma incurvum var. aztecum (Lepidoptera: Lasiocampidae) of Xochimilco, Federal District, Mexico. Folia Entomol. Mex. 66:31-45.