4/8 ENTOMOLOGICAL NEWS. [Dec., 'ij 



?nd by Gross (1912). In the discussion of germ bands (p. 23,0, the 

 fact that other Odonate embryos than the one chiefly described 

 (Calopteryx) have not immersed, but superficial, germ bands is not 

 mentioned. Brandt's text and figures (reproduced as G and H on p. 

 231), as well as a consideration of the mechanics involved, necessi- 

 tate the thickening and contraction of the serosa after, and not before 

 (p. 238), the rupture of the fused amnion and serosa. The length 

 of embryonic life is often more than three weeks (p. 242), in coun- 

 tries with a marked winter; the reviewer is accustomed to obtain 

 young larvae of Sympetrum vicinum in Philadelphia for class work 

 from eggs laid in late September or early October: kept indoors, 

 these hatch in December and January: in their natural surroundings 

 the embryonic period must be still longer. Semi-Arians of the twen- 

 tieth century may reject Mr. Tillyard's "homochrome" (pp. 254, 257) 

 for "homoeochrome," but, irrespective of orthodoxy, it may be ques- 

 tioned why "heteromorphic" should be employed in the sense of 

 "rarer" (p. 257). 



The characters for many of the taxonomic groups given in chapter 

 XIV, such as "Triangles short" or "Triangle not excessively nar- 

 rowed," without any accompanying mention of some neighboring 

 structure or detail to be used as a scale in measuring the shortness 

 or the narrowing, are not sufficiently precise to be available for pur- 

 poses of identification, however meaningfull they may be to those al- 

 ready acquainted with the Odonata. The non-comparative nature of 

 the tribal characters of the Libellulinae (pp. 269-273) makes determi- 

 nation of specimens exceedingly difficult, if not impossible. There 

 is not space within the limits of this review to discuss the classifi- 

 cation itself. 



"Nebraska" (p. 282) is an error for "Nevada," and "Diastatomma 

 Brauer" (p. 307, footnote) for "Diastatomma Burmeister-Charpentier." 

 The fact that one specimen of Phcnacolcstcs parallclus has been 

 found with wings outspread* does not seem to the reviewer to jus- 

 tify the conclusion that this extinct genus used to rest in that position 

 (p. 315). The condition shown by the fossil may only mean that the 

 insect had been softened by water and its wings floated out into the 

 attitude in which they are now found. Mr. Tillyard's own observa- 

 tions that females emerge, on the average, a few days before the 

 males (p. 326) and that birds seldom succeed in catching dragon- 

 flies (p. 330) are not in accord with records from other sources. His 

 method of "bristling" specimens, which does not include the head 

 and prothorax (p. 355), is surely faulty, as everyone who has worked 

 with the older collections, including that of de Selys himself, can 



* Reference is doubtless made to figure 4, page 574 of volume xlii, 

 The .liuerican Naturalist, Sept., 1908. 



