320 BIBLIOGRAPHY OF ECONOMIC ENTOMOLOGY. 
2287. [Riley, C. Y., 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—Oyiposition of Hylurgus 
pinifex, 2S0—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* 
insects, 286—Probable descent of Orthoptera, Pseudoneuroptera, 
and Dermatoptera from a Thysanuran form, 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 Ephern- 
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 ihe 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 
Sialidee, 297; of thysanuriform larvae, 297—Diversity of Neu- 
ropterous larvae, 297—Larvae of Sialidae, 297; of Hemerobiidse, 
297; of Trichoptera, 298; of Panorpidse, 298—Significance of 
the abdominal legs of Panorpid 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 iu Coleoptera, 300—Structure of maxillae in the several 
families, 300—Close resemblance of the mouth-parts of Elaterid 
