﻿isro.] 179 



than one. It does not appear, then, why the Cynips should not come 

 forth uninjured ; as the contents of these large galls seem to be more 

 than enough both for the legitimate owner and the intruders billeted 

 upon him. These guest-gallflies have been a fruitful source of error 

 to observers. No less than 7 of the species described by Linne as 

 raising galls, are in fact referable to the genus Synergus. The nume- 

 rous species have found no describer but Hartig, whose brevity renders 

 it unlikely that any one should succeed in identifying them with 

 certainty. The second group, the ApJiidivorcd, consists of the nume- 

 rous and minute species of the genus Alloiria, which live in the larval 

 and pupal states in the bodies of plant-lice, and stand first among the 

 genuine parasites. They are distinct from those which follow by their 

 structure, which closely resembles that of Cynips. The members of 

 the third* group are all true parasites, infesting various insects, and 

 especially, it would seem, appointed to keep down the numbers of the 

 Dipterous order. I shall now give a short table of the British genera, 

 before proceeding in my proposed attempt to reckon up the indigenous 

 species. 



I. Facies prope clypeum striolata. Prono- 

 tum sensim declive. Terebra exserta. 

 Coxse posticos distantes I. stneegus, Hart. 



II. Facies baud striolata. Pronotum verti- 

 cale. Terebra baud exserta. Coxse 

 posticas approximatse. 



A. Scutelli fovea cyathiformis, marginata. 

 Abdomen segmento 2 do maximo, cete- 

 ris brevissimis. (Eucoilidas?) 



a. Alse apice integral, nee ciliatse. 



h. Abdomen segmento 2 d ° basi baud 



tomentoso 5. cothonaspis, 



lb. Abdomen segmento 2 do basi to- "' ° lb ' 



mentoso. 



c. Metapleurro haul tomsntosas. 

 Alae completae. Antennarum 

 articulus 1™ 2 do longior 4. eucoila, "Westw. 



cc. Metapleurae tomentosa?. Aloe 

 abbreviate. Antennarum ar- 

 ticulus l us 2 d0 parum longior.. 6. glaukaspidia, Thorns. 



* According to Walsli, the genera Au'nx, Ambrynotus, and Sarothrus are inquilines. Some of 

 the European species of Aulax certainly make galls. Of the habits of the other two nothing is known 

 in Europe; and it ;:eems better to leave our species where they are lor the present. — T. A, M. 



