320 BIBLIOGRAPHY OF ECONOMIC ENTOMOLOGY. 



2287. [EiLEY, C. V., et aL] Continued. 



CHAPTER X Continued. 



The development of the bark-boring beetles Hylurgops and Xyle- 

 borus. By A. S. Packard, jr 280 



Breeding habits of Xyleborus ccelatus, 280 Oviposition of Hylurgus 

 pinifex, 280 Egg of the Xyleborus, 24 hours after impregnation, 

 280 More developed egg, 280 Threads connecting the amnion 

 with the serous membrane, 281 Dorsal view of the embryo, 281 

 Later stage in Hylurgops, 281 Later stage in Xyleborus, 281 

 Number of pairs of spiracles, 281 Structure and habits of freshly 

 hatched Hylurgops, 281. 

 The number of segments in the head of winged insects. By A. S. 



Packard, jr 282 



Views generally entertained on this subject, 282 Head composed 

 of four segments, 283 The procephalic lobes form the antennal 

 segment, 284 The clypeus and labrum are the tergal portion of 

 this segment, 284 The epicranium is the pleural portion, 284 

 The occiput is the tergal portion of the labial segment, 284 The 

 gular region probably the base of the labium, 285. 

 CHAPTER XI: 



The systematic position of the Orthoptera in relation to other orders 



of insects. By A. S. Packard, jr 286 



Review of the characteristics of the four lowest orders of winged 1 

 insects, 286 Probable descent of Orthoptera, Pseudoneuroptera, 

 and Dermatoptera from a Thysanuran fo,rm, 286 Method of the 

 present study, 286 Characters of the Phyloptera, 287 Mouth- 

 parts, 287 Thorax, 287 Wings, 288 Abdomen, 288 Metamor- 

 phosis, 288 Nomenclature of external parts of Arthropoda, 288 

 Sequence of orders of Phyloptera, 288 Characters of Dermatop- 

 tera, 289 ; of Orthoptera, 289 ; of Pseudoneuroptera, 290 Want 

 of uniformity in characters of Pseudoneuroptera, 290 The diag- 

 nostic characters superficial, 290 Structure of labium, 291 

 Relative proportions of head parts, 291 Subdivisions of the order, 

 292 Characters of Platyptera, 292 ; of Odonata, 292 Of Ephem- 

 erina, 293 Characters of Neuroptera, 293 Ligula, 293 Thorax, 

 293 Wings, 293 Abdomen, 294 Subdivisions of the order, 294 

 Tabular view of the grand divisions of winged insects, 294 Dia- 

 grammatic view of the genealogy of the insects, 295 Genealogy 

 of the Hexapoda, 295; of Thysanura, 295; of Dermatoptera, 295 ; 

 of Orthoptera, 296; of Pseudoneuroptera, 296; of Hemiptera, 

 297 ; of Neuroptera, 297 Derivation of cruciform larvae, 297 ; of 

 Sialidse, 297 ; of thysanuriform larvae, 297 Diversity of Neu- 

 ropterous larvee, 297 Larvae of Sialidte, 297 : of Hemerobiidae, 

 297; of Trichoptera, 298; of Panorpidae, 298 Significance of 

 the abdominal legs of Pauorpid larvae, 299 The hypermetamor- 

 phosis of Mantispa a key to the origin of a complete metamor- 

 phosis, 299 The aspect of the Neuroptera comparatively special- 

 ized and modern, 299 The Neuropterous labium a secondary 

 product, 299 Origin of the Coleoptera, 299 The free, active 

 larvae of the carnivorous groups most nearly allied to the primi- 

 tive form, 300 The scavenger and phytophagous larvae show 

 increasing degradation of development, 300 The relative form 

 of the maxillae a good index of the general development of the 

 body in Coleoptera, 300 Structure of maxilLe in the several 

 families, 300 Close resemblance of the mouth-parts of Elaterid 



