259] THE LARVAE OF THE COCCINELLIDAE—GAGE 27 



SYNOPSIS OF LARVAE 



In the taxonomic study of any group of organisms, the investigator 

 should not draw conclusions from characteristics which upon the surface 

 may show a high degree of specialization or generalization, without first 

 making a careful study of these characteristics, no matter how important 

 or unimportant they may seem. According to Comstock, "The logical 

 way to go to work to determine the affinities of the members of a group of 

 organisms is first to endeavor to ascertain the structure of the primitive 

 members of this group; and then endeavor to ascertain in what ways these 

 primitive forms have been modified by natural selection." With such a 

 view as this in mind, the taxonomist must not only study the members of 

 the group upon which he is working, but he must also endeavor to ascertain 

 the conditions that existed in the progenitors of the group. It is obvious, 

 then, that those conditions in the chosen group which are most nearly 

 similar to the conditions in their progenitors are the most generalized; 

 further, that those individuals possessing these primitive characteristics 

 are the generalized individuals of the group. There are often two or more 

 sets of prominent characters, and many times these may not run in parallel 

 lines, but seem to contradict each other or to run in opposite directions. 

 For instance in the larvae of the Coccinellidae that form which shows the 

 most generalized condition of the head sutures, the Epilachninae, have 

 also what seems to be the most highly specialized condition of the setae 

 or scoli on the body; and Hyperaspini which have the most highly special- 

 ized condition of the head sutures show what appears to be the most 

 generalized condition of the setae. 



If one studies the conditions present in the Chrysomelidae, the prob- 

 able progenitors of the Coccinellidae, he will find in the genus Chelymorpha 

 conditions of the epicranial suture and scoli similar to those found in the 

 Epilachnini. The epicranial stem in Chelymorpha is long and the epi- 

 cranial arms are gradually divergent, a condition almost identical with 

 that of the Epilachninae. The members of the subfamily Coccinellinae 

 have a much shorter epicranial stem or in many genera it may be entirely 

 wanting and the epicranial arms diverge immediately from the occipital 

 foramen. Even the epicranial arms are wanting in the adult larvae of 

 Scymnus and H)rperaspini; while the clypeal suture, which is distinct and 

 entire in Chelymorpha and Epilachna, is incomplete and only indicated 



