103] LEPIDOPTEROUS LARVAE — FR ACKER 103 



The genera may be distinguished as follows: 



a. Body not bearing prominent lateroventral protuberances. 



b. Body depressed ; head depressed, partially retractile. Heteropacha 

 bb. Body cylindrical ; dorsal setae as long as lateral setae. 



e. Head black, with epicranial suture inconspicuous; labral notch 



always deep. Malacosoma 



cc. Head with epicranial suture forming a conspicuous yellow 



inverted Y on the black background, or with pale lateral areas ; 



labrum sometimes only shallowly emarginate at apex. 



Gloveria 



aa. Body bearing conspicuous lateroventral protuberances, longest on 



prothorax, where they are proleg-like ; longest setae situated on these 



protuberances, dorsal setae very short or absent. 



b. Body segments each with a pair of verruca-like swellings on the 



dorsum, those of segment 8 subequal in size to those of other 



segments. Tolype 



bb. Body segments without paired dorsal verruca-like swellings, 



but a short fleshy dorsal horn on segment 8. Epicnaptera 



Heteropacha rileyana is small and onisciform in shape. It is more 

 closely related to Tolype than to Malacosoma, but the fleshy processes 

 are reduced. 



Of Malacosoma, eight species are found in the United States. Most 

 of them are large and cylindrical caterpillars with long setae. There is 

 considerable variation in color. A table of the species has been written 

 by Dyar and will be found in the Canadian Entomologist, 25, 1893, 

 p. 43. 



Gloveria arizonensis and G. howardi, the only species of this genus 

 examined, overlap Malacosoma in most characters. In arizonensis the 

 labrum has a very shallow emargination, while in the other species it is 

 notched to about one-half its depth. 



Tolype velleda has the body very much depressed and this appear- 

 ance is increased by the long setae between the spiracles and prolegs. 

 The venter is almost naked. The setae are grayish brown and the body 

 is inconspicuously marked except for a dorsal black transverse vitta on 

 the metathorax. The dorsal metathoracic verrucae are more prominent 

 than those of any other segment. Tolype laricis is similar, except that 

 the verrucae of the metathorax are not increased in size. 



Epicnaptera americana is a large species with the setae reduced 

 in size in the later stages. The prothoracic protuberances on each side 

 are very large. 



Family Eupterotidae 



This European family includes the American genus Apatelodes, 



