1885.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 419 



the State. Three other specimens, consisting of one male and two 

 females, were also bred at Washington, July 31, and August 8, 1883, 

 from coarctate larvae received a few weeks before from Mr. J. G. Bar- 

 low, of Cadet. Mo. 



That there can be no question as to the identity of the parasite I will 

 state that the specimens just mentioned were carefully compared, not 

 only with Professor French's description, which might leave a doubt, 

 but also with type specimens of both sexes received from him. 



In the genus Uupelmus there is great want of uniformity of habit in 

 regard to host, while in most other Chalcid genera the uniformity in 

 this respect is very marked. On account of this polyphagic habit, as 

 well as by virtue of its other peculiarities, the genus long ago inter- 

 ested me, and I have obtained it from Lepidopterous eggs, from Or- 

 thopterous eggs, from Hemipterous eggs, from Cynipid galls, from 

 Cecidomyid galls, from Lepidopterous larvae, from Coleopterous larvae, 

 and from free Cecidomyid larvae. 



I am not aware that this species has ever before been bred from the 

 Hessian Fly, although it may be the fourth parasite mentioned so in- 

 definitely by Herrick.* 



Tetrastichus productus n. sp. 



[Plate XXI, fig. 5.] 



This species was bred in considerable number March 31, 1884, from 

 coarctate larvae sent by Mr. Barlow from Missouri the summer previous. 

 It is impossible from the evidence we possess to say with certainty 

 whether this species is really a parasite upon the Hessian Fly or whether 

 it is a secondary parasite, having some one of the other i^arasites as its 

 proper host. This is always an extremely difficult point to determine, 

 in considering any insect from which several species of parasites have 

 been bred. In such cases all of the parasites have usually been de- 

 scribed as primary^ i. e., true parasites of the species from which they 

 were reared ; but the habits of the genus, so far as known, should guide 

 us in our conclusions, in default of absolute data or direct observation. 

 Several cases have come under my notice in which Tetrastichus was 

 without question a secondary parasite and several more are given by 

 Giraud and Laboulbene.t From these facts I am stronglj' inclined to 

 believe that the species of Tetrastichus are usually, if not invariably, 

 parasitic upon the smaller Hymenoptera belonging to the Chalcididae, 

 Cynipidae and Braconidae, and I am thus inclined to consider T. produc- 

 tus not as a parasite of the Hessian Fly, but a secondary parasite feed- 

 ing upon some one of the others, and probably upon Merisus destructor. 



* Americau Journal of Science and Arts, vol. xli p. 155. New Haven, October, 1841. 

 tListe d'Eclosions d'Insectes. Ann. de la Soc. Ent. de France, t. vii, Ser. V, pp. 

 433,444 (1877). 



