June, 1S96.] GrOTE : On DISTRIBUTION AND MlMICRY OF APATELA. S3 



barriers. There is also the dependency upon food plants and geog- 

 nostical conditions to be considered. At any rate, the central Cali- 

 fornia fauna must be studied from the point of view that it is isolated 

 upon a comparatively narrow strip of land as compared with the fauna 

 east of the main range. And this view must be taken of the fauna of 

 the West Coast, boili in North and South America, wedged in as it is 

 between the sea and the mountainous backbone of the New World. 



The very near relation between the moths of psi, frtdens and ocd- 

 deiitalis, while the larvae are so strikingly different, recalls the case of 

 Datana and Phalera, though here the larval characters are decidedly 

 stronger and even structural. We may assume that here the tendency 

 to split into distinct larval forms was early developed, and that it ex- 

 emplifies the fact that specific characters in Apaiela are best, perhaps 

 first, expressed in the younger stages. The two European species seem 

 altogether nearer, and lead to the impression that they have a more im- 

 mediate connection, while the American probably left the common an- 

 cestor at the close of the Tertiary. 



In 1894, Dr. Harrison G. Dyar discussed the appearance of the 

 larvre of Apatela, and his remarks are in part applicable to the Euro- 

 pean forms. The diversity is mainly ascribed to a "mimicry of all 

 sorts of objects, from that of resemblance to the foliage {grisea, tritona), 

 to warning colors {ohliniid) and mimicry of special objects, such as 

 spider's nest {yulpina) or of some other specially defended larva ( r ad- 

 cliff ei w\\m\c% Datana, or liiteicovm, which probably mimics Orgyia)y 

 Previously, in 1S93, Dr. Chapman had discussed the mimicry of the 

 larvffi as follows: "The protection which the full grown larvae have 

 from their enemies, owing to their special form and coloring, is a mat- 

 ter that in its details, has very largely eluded me ; I have, in fact, seen 

 very few Ciispidia in the wild state. Psi and tridens are usually con- 

 spicuous ; strigosa no doubt closely assimilates to a hawthorn leaf with 

 a bit of brown dead leaf or twig. My observations on kporina were 

 made and repeated a good many times on the green white-haired form 

 occurring on alder ; this larva sits somewhat curled round, near the 

 middle of the underside of a leaf. Looking down from above it is ab- 

 solutely hidden, looking up from beneath it ought to be very evident, 

 but this is far from being the case. I have several times missed a larva 

 till I have looked three or four times, and have also fancied I saw a 

 larva when none was there. In looking up from below through the 

 foliage of an alder tree, most of the lower leaves are in the shade of the 

 upper ones, but here and there a gleam of light falls through on to a 



