OF WASHINGTON. 101 



NOTES ON THE GENUS METOPIUS, WITH DESCRIPTION 

 OF A NEW SPECIES AND TABLE OF SPECIES. 



BY C. L. MARI.ATT. 



Prof. Riley recently received from Mr. Lawrence Bruner a 

 peculiar Ichneumonid which had been collected in South 

 Dakota by Mr. J. M. Aldrich. An examination showed at 

 once that it was a female belonging to the genus Metopius. I re 

 called having collected two specimens of a closely allied, if not 

 the same, insect in Kansas, and had them forwarded to me. 

 They were duly received, and proved to be identical with the 

 Dakota specimen, and were both females. These three females, 

 together with two additional females received later from Mr. 

 Aldrich, while belonging undoubtedly to the genus Metopius, 

 differ in a very striking manner from males of several species 

 in the National collection there being no females represented 

 and might even be considered to belong to an entirely distinct 

 genus. So strikingly do they differ from the males seen, and 

 from the description of the genus by Gravenhorst, and later 

 by Brulle, and also from all the descriptions of females, most 

 of which I have been able to consult, that it struck me very 

 forcibly at first that perhaps a female of this genus had never 

 been characterized, and that the supposed females described 

 were in reality males ! Examination, through the kindness of 

 Mr. Cresson, of the specimens of this genus in the collection 

 of the American Entomological Society at Philadelphia, sub 

 sequent to the reading of this paper, showed me that I was in 

 error in this, but indicated very plainly that my specimens 

 differed very materially from all other described species and 

 also in important particulars from the genus as at present 

 understood. 



The genus Metopius is perhaps better characterized and more 

 distinctly separated from other genera than any other genus of 

 Ichneumonidae. The peculiar features are the very prominent 

 shield on the face, the antennae, the character of the thorax 

 and venation of the wings, in all of which particulars my 

 specimens agree ; but the description of the genus by Graven 

 horst and Brulle, and also of all the species which I have been 

 able to consult, agree in describing the abdomen of both the 

 male and female as completely depressed at first with the 

 sides nearly parallel, and then slightly widening posteriorly. 

 The ovipositor is said to be nearly concealed, and in the case 

 of the females examined by me, and so far as indicated by the 

 descriptions of the others, is of small size, not exceeding, 

 when fully exserted, one-fourth the length of the abdomen. 



