SYNOPSIS. XIX 



carrying pollen, 226. Membranous character of the wings, 

 signiticance of term *' Hymenoptera," 227. Adaptations of wings 

 for swift flight, 227. Modification of ovipositor into sting, 227. 

 Home -making instinct of bees, 227. Specialization of function 

 illustrated by a colony of bees, consequent specialization of 

 structure, 228. Cells of the comb not mathematically exact, 

 228. Darwin's observation on progress in cell-making in pass- 

 ing from humble to hive bee, 228. Helplessness of larvce, 228. 

 Tender treatment of old bees towards their young compared 

 with indifference of locusts and fostering "tare of the more 

 specialized vertebrates, 229. Length of pupal stage, 229. Length 

 of Ufe of worker and queen, 229; habits acquired during adult 

 life, 229. References on bees, 230; Hymenoptera Terebrantia, 

 231. Tenthredinidne, 231. Broad junction of thorax and abdo- 

 men, 231. Biting mouth parts, 231. Ovipositor modified into 

 a saw, 231. Habits and structure of larvae similar to those of 

 Lepidoptera, 231. Uroceridae, 232. General characters, 232. 

 Tendency of first abdominal ring to join thorax, 232. Ovipositor 

 modified into a borer, 232. Absence of abdominal prop-legs in 

 larvce, 233. Cynipidae, 233. General characters of gall-flies, 

 233. Galls the homes of the larvae, 233. Degraded condition 

 of mouth parts, 233. Oak-apples, 233, 234. Spring and fall 

 gall-flies, 234. Osten Sacken on Cynipidae of North American 

 oaks, 234. Chalcididae, 235. Males of Blastophaga, wingless, 

 females winged, 235. Ichneumonidae, 235. Power possessed 

 by Thalessa atrata of raising and lowering its abdomen, conse- 

 quent aid given the ovipositor, 235, 236. Method of oviposition, 

 236. Riley's observations, 236. Ichneumon-flies with short ovi- 

 positors, 237. Snellen Van Vollenhoven's Pinacographia, 237. 

 Hymenoptera Acuteata, 238. Formicidas, 238. Thoracic rings 

 of wingless worker and soldier more loosely connected than in 

 winged male and female, 238. Pedunculated abdomen of sting- 

 less and stinging ants, 238. Organs of sight, 238. Adaptations 

 of mandibles to work performed, 238. Architecture of ants, 

 239. Specialization of function and structure illustrated by a 

 colony of ants, 239. Helplessness of larvae, 239. Cocoon of 

 Formica fusca, 239. Short duration of pupa stage, 239. Social 

 life resulting in habits of co-operation, 239. Lubbock's experj- 



