112 



PSYCHE. 



[July 1891. 



Seventh stage (9 larvae only). Head 

 pale yellow minutely mottled with grayish 

 spots; lahrum, antennae and a spot before 

 the eyes, white; ocelli and jaws black; width 

 3.5 mm. The body is as in the previous 

 stage, but the warts on the cervical shield 

 are not distinctly darker. The dorsal black- 

 ish or pale gray shade is in triplicate on 

 joints 3 and 4. Spiracles white in a fine 

 black border. The body is often bright yel- 

 low, as are the dorsal tufts, and even the 

 hair is yellowish. 



Cocoon. Double, thin, made of silk and 

 the hairs of the larva. 



$ Pupa. Cylindrical, the abdominal seg- 

 ments tapering, the eyes, wing cases and an- 

 tenna cases especially prominent; a little 

 depressed behind the thorax. Semi-trans- 

 parent, shiny yellowish white, the back cov- 

 ered with long, thin, silky white hairs; cre- 

 master flat, terminating in several brown 

 hooks well fastened in the silk of the cocoon. 

 Length 12 mm. ; width 5 mm. 



5 Pupa. Robust, thickest through the 



2nd to 4th abdominal segments, elsewhere 

 smaller, of nearly even width ; thorax and 

 head small, no wing cases, leg cases small. 

 Last segment rounded, cremaster flat, lather 

 broad at base, terminating in a number of 

 brown divergent hooks. Color semitrans- 

 parent, shiny, very pale yellowish, without 

 marks. Over the dorsum considerable fine, 

 rather long, whitish silky hair. Length 18 

 mm., greatest diameter 8 mm. 



$ Imago. Of the same structure as O. 

 leucostigma, but not white, the color of the 

 down, which is especial ly abundant on the 

 ventral side, being light brown. A small 

 black spot on the second abdominal segment. 

 The rudimentary wings are dark cinereous. 

 The J imago is very similar to O. leucostig- 

 ma, but can be distinguished by its darker 

 color and heavier black markings. 



Food plants. Dr Thaxter gives oak, but I 

 have found the species as omnivorous as O. 

 leucostigma. My specimens were fed mainly 

 on maple and witch-hazel. 



THg GERM-BAND OF INSECTS.* 



Those who have watched the advance in 

 our knowledge of insect embryology during 

 the past three or four years will be deeply 

 interested in Prof. Graber's latest treatise. 

 Like his muscid paper it represents many 

 years' study, but unlike that work it covers 

 a very considerable ground, being a compre- 

 hensive description of the germ-band of a 

 number of insects. The species investigated 

 belong to the genera: Lina, Lema, Tele- 

 phone, Melolontha, Hydrophilus; Pieris, 

 Gastropacha, Bombyx, Zygaena ; Hylotoma ; 

 Stenobothrus, Mantis, and Gryllotalpa. It 

 will be seen that this list comprises repre- 



* Vergleichende studien am keimstreif der insecUn, 

 von.Veit Graber. Denkschr. d. math, naturwiss. 

 c lasse d. k. akad. d. wiss. Wien. Bd. 57, 1890,621- 

 734. 12 colored plates. 4°. 



sentatives of four of the important orders. 

 Prof. Graber treats of the formation and 

 method of growth of the germ-band, its re- 

 lations to the envelopes (amnion and serosa), 

 its segmentation (both internal and external) 

 and its appendages. Chapters are introduced 

 on the formation of the germ-layers and on 

 the origin of the body spaces. Many pages 

 are given up to a minute and critical discus- 

 sion of the results achieved by other investi- 

 gators. The work concludes with a long 

 chapter on the development of the nervous 

 system. 



In a brief sketch we cannot hope to do 

 justice to the mass of matter with which 

 Prof. Graber presents us; it will be possible 

 to touch on only a few of the questions with 

 which he attempts to deal. Before so doing 



