46 BRITISH ICHNEUMONS. {Thersilochus 



now in my collection, together with a full series from the same source. 

 Tuck and I have taken a very few females by sweeping and on flowers of 

 Heracleum spho7idyliit7n at Tostock, Farnham and Southwold in Suffolk ; 

 and I have one from Pifiard's Felden collection ; these were captured 

 between the beginning of June and of July. 



5. nitidus, Bridg. 



Thcrsilochtts nitidus, Bridg. Trans. Ent. Soc. 1889, p. 430, T . 



A shining badious-black species. Head transverse, broader than 

 thorax and subdilated behind the eyes. Antennae about three-quarters 

 as long as the body, with scape and part of basal flagellar joints fulvous ; 

 flagellum apically subclavate, with fourteen joints in both sexes of which 

 the first is once and a half longer than broad, and about a quarter longer 

 than the second ; all joints longer than broad. Thorax with mesonotum 

 nitidulous and obsoletely punctate ; metathorax with no taace of areae. 

 Abdomen hardly as long as head and thorax ; basal segment short and 

 about twice and a half longer than broad, nearly straight, only slightly 

 narrower at base than apex, with distinct and subcentral spiracles ; 

 second segment transverse and apically as broad as thorax ; anal segments 

 subcompressed ; terebra slightly reflexed and hardly longer than first 

 segment. Legs somewhat slender and entirely fulvous, or with hind 

 coxae, etc., infuscate. Wings with tegulae black ; stigma and nervures 

 subtestaceous infuscate ; radial nervure apically curved. Length, 1.5-2 mm. 



"This very small insect might almost form a separate genus : the ist 

 segment of the abdomen is shorter and thicker than usual," says its author, 

 who does not compare it with his T. minutus, placed by Szepligeti in the 

 subgenus Phradis. This species and T. carinattis have hitherto been 

 ignored by Continental authors, because they were not referred to in 

 Thomson's 1889 paper. 



The male has not before been described, but differs only sexually from 

 the female. 



The hitherto unique female was captured by the Rev. T. A. Marshall 

 in Britain, though no locality is indicated. I have only once met with 

 this species, which must be extreme!}- local or retiring; on the 14th June, 

 1900, both sexes in about equal proportion \vere in the utmost profusion 

 on the flowers of mustard (]3rassica sinapistnnn) growing among turnips 

 ( B. rapa) in a field at Cavendish in Suftblk, where they may be suspected 

 of preying upon Caitlwrrhyiuhiis pkurosligma or some allied weevil sub- 

 sisting upon one or both of these plants. 



6. morionellus, Holiitgr. 



Thersilochus morionellus, Holmgr. Sv. Ak. Handl. 1858, p. 139; Thorns. O.E. 

 xiii. 1386, ? ; Brisch. Schr. Nat. Ges. Danz. 1880, p. 193, 3 . Isurgus morionellus, 

 Szepl. Ann. Mus. Nat. Hung. 1905, p. 531, ? . 



Head slightly shining and as broad as thorax with vertex broad and 

 both slightly and roundly elongate posteriorly ; temples dull and cheeks 

 short ; clypeus distinctly discreted, apically truncate and, with mandibles 

 and palpi, flavidous. Antennae not extending beyond thorax, infuscate 



