140 DR. PACKAUP. 



great enough to separate the Linnaean Neuroptera into two 

 independent orders or suborders (whichever we may choose 

 to call thera), T now ask if embryology does not give inde- 

 pendent testimony as to the close alliance at least of the 

 Libellulidae and Henierobidae, even if we go no farther ? 



The only Coleoptera with whose development we are 

 acquainted is Donacia, worked out more carefully by Melni- 

 kow than any one else. During this summer I have studied 

 Teleplwrus fraxini and Attelahus rhuis in nearly all their 

 embryonic stages. Attelabus is developed in the same 

 manner as in Donacia. There is a parietal (" amnion") and 

 a visceral membrane in Attelabus ; (it was not observed in 

 Telephorus, though it doubtless exists), as in Donacia. In 

 Attelabus, however, the primitive band rests on the out- 

 side of the yolk, while in Telephorus it floats in the yolk, 

 and forms a sigmoid band, extending back to the posterior 

 pole of the egg. But after the rudiments of the limbs appear, 

 the embryology of both genera accords with that of Donacia. 

 I have found that the embryology of Gastrophysa ccBrulei- 

 penjiis in its later stages also agrees with that of Donacia 

 (both being Chrysomelids). A study of the development of 

 Nemattis reidricosns shows us that its embryology accords 

 witli that of Apis wclUfca. The formation of the blastoderm 

 is as described by Biitschli in Apis,^ and quite like that of 

 the Formicidse as studied by Ganin. It also agrees with 

 that of the Diptera in most particulars. 



There is indeed a remarkable uniformity in the mode of 

 development of the Hexapoda, as much so, perhaps, as in the 

 Crustacea (Malacostraca), and it is difficult to determine 

 what embryological characters may be set down as distin- 

 guishing even the different suborders. These characters, 

 whatever they may be, do not probably reside in the em- 

 bryonal membranes, or in the relation of the primitive band 

 to the yolk. Perhaps they will be found in the form of the 

 advanced embryos. For example, we now know that the 

 embryos of the Isopod Crustacea only differ from those of 

 the Amphipods while in the egg by having the end of the 

 abdomen bent over the back, while in the latter (Amphi- 

 pods) it is curved beneath the body, as pointed out by Fritz 

 Mliller. The spiders and scorpions also pass through a 

 similar course of development, and the Mites (Acarina) are 

 developed in a manner either identical with the spiders in 

 some genera, or more like the Hexapods in others. We 

 know almost nothing of the embryology of the Myriapods, 



1 Dr. 0. Biitschli, "Zur Entwicklungsgescliichte derBiene," 'Siebold UDd 

 Ivolliker's Zeitsclirift,' 1870, p. 519. 



