Sept., '05] ENTOMOLOGICAL NEWS. 243 



both in pleasure and in usefulness, than the random description of numer- 

 ous new species." 



Mr. Aldrich's catalogue covers 680 pages. Osten Sacken's 324 pages 

 were of much smaller size. The new catalogue is printed on good paper, 

 the New Era presswork guaranteeing its pefect typography. I understand 

 it is to sell for $1.50. Its references are brought down to January i, 1904, 

 but the appendix lists the papers and new species that have appeared 

 during the year 1904, so that the catalogue is brought to date. The 

 writing of the catalogue has covered seven years' time, the presswork has 

 required nearly a year. Every dipterologist feels a debt of gratitude to 

 Mr. Aidrich, and we all wish to congratulate him on the successful com- 

 pletion of his great task. I am sure I shared with him some of the elation 

 of its completion when I received his postal announcing "It's out." — 



A. L. Melander. 



9 



The Development of Certain Hvmenopterous Parasites. 



Among the most interesting of entomological problems are those con- 

 nected with the biology of parasitic insects. The method of respiration, 

 of feeding, and the molting of the skin are illustrations of unsatisfactorily 

 solved problems. Another puzzling phenomenon has been the number 

 of parasites which may develop within a single host. Pergande reared 

 twenty-five hundred specimens of the Chalcid Litoitiastix truncatella from 

 a larva of Plusia brassicee. Giard, '98 (Bull. Soc. Ent. Fr. ,p. 127), re- 

 ports almost three thousand from a single Plusia gamma. The problem 

 becomes yet more difficult when we consider that, as Giard points out, 

 the adult female parasite does not contain more than a hundred mature 

 eggs. It has been supposed that in cases of excessive infestation the 

 host had been attacked by more than one female. If the required twenty- 

 five or thirty parasites may oviposit within a single host it is certainly not 

 to be expected that any of the larvae should escape, as is always the case. 

 Some recent work on a related form, by the French entomologist, P. 

 Marchal, not only throws light upon this question but reveals a phe- 

 nomenon of surpassing interest to the embryologist. Briefly announced 

 in 1898* and published in detail within the past year, f his discovery 

 seems to have escaped almost entirely the attention of American workers. 

 Aside from a bare mention in Howard's " Insect Book" I find no refer- 

 ence to his work, and it therefore seems not inappropriate to bring it to 

 the notice of readers of the News. 



In 1892 Bugnion i published a valuable research upon the postembrj- 

 onic development, anatomy, and life-history of Ageniaspis fuscicollis 

 {Encyrtus fuscicofiis Dalm.) which is parasitic on various larvae, among 

 others those of Hyponomeuta cognatella. In the latter part of May are 

 to be found within these larvae the embryos of the parasite, enclosed 



* Comptes Rendus Ac. Sci., t 126, pp. 662-664. 



t Arch. d. zool. exp^r., et g^n^rale, 2 ser.. t 2, pp. 257-335, pi. 9-13. 



X Rec. zool. Suisse., t. 5, pp. 471-534. P'- 22-25. • 



