258 ENTOMOLOGICAL NEWS. [Oct., '05 



The larvae of Illicc faustinula were found by me in February, 

 1904, near Stanford University, on the under side of fence- 

 rails upon which grew Ramalina mcnziesii Tuck. , and other 

 lichens which the insects mimic in color. The larvae were 

 found also on various trees bearing patches of their food-plant. 

 They rest during the day in shady spots on the fences or trees 

 and feed by night. When at rest, the anal prolegs of the 

 larvae point directly backwards. Towards the middle of 

 March, faustinula spins its weak cocoon of fine silk inter- 

 mingled with its hairs and forms a short, stout, brownish pupa 

 much like that of an arctian, paler ventrally and with' a pale 

 longitudinal band on the dorsum of the thorax. Length 

 8 mm., 'width 3.2 mm. 



In San Francisco the larvae are not fully grown until June ; 

 they may be found throughout the winter, there being but 

 one brood annually ; the younger larvae differ but little from 

 the mature ones. These larvae are great spinners, spinning 

 all over their food-plants in captivity and can suspend them- 

 selves by a thread in all stages. With all this spinning pro- 

 pensity, they make a very weak cocoon in some chink or 

 crevasse ; they are rather sluggish in their motions. 



Last year I reared but few imagines, which all proved to be 

 Illicc ncxa ; this year, however, Mr. Griunell raised a larger 

 number of imagines, some of which proved to be ncxa and 

 some faustinula. Both of these forms were obtained from 

 caterpillars not differing in any way, and in some cases most 

 probably from larvae hatched from one batch of eggs, as many 

 caterpillars were taken from the same fence- rail. Of the imag- 

 ines reared, most were faustinula, but $ and ? 9 of both 

 forms were obtained from the numerous larvae. An examina- 

 tion of the male genitalia by Mr. Grinnell showed that they 

 were the same in both forms. 



From a large series of both forms it was found that fa it si i- 

 nula and ncxa iutervaried to a considerable extent, so that 

 both forms could be fairly well connected with one another by 

 intermediate variations. 



Illicc ncva and faustinula were also raised by Dr. Ik-hr from 

 larvae from Napa County, California, but we have no particu- 

 lars from him regarding the larva-. 



