XX SYNOPSIS. 



ments on the intelligence of ants, 240; structure and develop- 

 ment, not mental qualities, the basis of a classification, 240. 

 References on ants, 240. Sphegidae, 240. Habit of paralyzing 

 insects, 240. Adaptations of mandibles and legs for digging 

 nests in the earth, 240. Diet of the larvae, 240. Preference of 

 different species for different kinds of insects, 240. Other fos- 

 sorial Hymenoptera, 241. Habits and structure of Pompilus 

 formosus, 241 ; Lincecum on the Tarantula — Killei' of Texas, 

 242. Vespidse, 242. Structure of Vespa inaculata, 242; shoulder 

 lappets similar to those of Lepidoptera, 242. Social habits, 243. 

 Construction of paper nests, 243. Larval characters, 244. Size 

 of forward end of body adapted to size of cell, 2^44. Apidce, 

 244. General remarks on the classification of the Hymenoptera, 

 244; reasons why this order is placed at the head of the insect 

 series, reasons why it should not be given this position, 244, 245. 

 Tenthredinidae more closely allied to Lepidoptera than any 

 other family of it^ order, 246. Possibility that Lepidoptera and 

 Hymenoptera had a common ancestor, 246. Reasons for the 

 obliteration of the caterpillar-like stage in Hymenoptera, 247; 

 replacement of this stage by the grub-like form, 247. Other 

 evidence of the convergence of the Hymenoptera and Lepidop- 

 tera, Walter's investigations, 247. 



ORDER XVI. — DIPTER A. 



Adult and larval stages of flies characterized by interesting 

 modifications of structure, 248. Tabanus a good type, 248. 

 Marked concentration of parts of body, 249; prothorax immov- 

 ably consolidated with mesothorax, large size of mesothorax, 

 complex structure of metathorax, 249. Discussion on the thorax 

 of Hymenoptera and Diptera, 249; Gosch's paper, 249; La- 

 treille's theory, 250. Views of Weismann, Hammond, and Pal- 

 men, 250. Pseudo-sessile abdomen of Tabanus, 25 1 ; difference 

 between this and the true sessile abdomen of the generalized 

 orders of insects, 251. Specialization of function correlated 

 with complexity of mouth parts, 252. Degraded structure of 

 mouth parts of Musca, 252. Peculiar adaptations of feet. 

 Home's figures, 252. Number of wings, significance of term 



