298 JOURNAL, BOMBAY NATURAL HIST, SOCIETY, Vol. XXVIII. 
No. XXXIV.—AN UNDESCRIBED NATURAL ENEMY OF THE CASTOR 
SEMILOOPER (ACH@A (OPHIUSA) MELICERTE, HMP.) 
(With a plate.) 
The semilooper caterpillar of the noctuid moth Achwa (ophiusa) melicerte 
Hmp.is a common and well known pest of the castor oil plant (Ricinus 
comunis) all over India. In many parts of the country, especially in 8S. India, 
this caterpillar is kept in check by an important natural enemy—a hymenop- 
terous parasite. In certain seasons this parasitic wasp has been found to 
exercise a very effective natural control over this pest, as many as seventy 
or eighty per cent. of the caterpillars being found dead in the castor plots. 
The presence of this parasite is easily detected in the fields by the charac- 
teristic appearance of its cocoon found attached as a sort of cushion 
underneath the tail end of each victimised caterpillar (see fig. 3). 
Though this parasitic wasp has been known to entomologists in India for 
some years past, it is curious that it has not been identified or described any- 
where till now. This is, of course, due to the fact that very little systematic work 
has been done by any one on the parasitic hymenoptera, a group of insects of first 
rate importance as natural enemies of various crop pests, and especially of the 
forms belonging to the family ‘ Braconidee’. For some time past I have been 
paying some attention to these insects and trying to do some systematic work 
and as far as I can make out from available literature, this insect does not appear 
to have been named or described anywhere. There are references to it in recent 
works on Indian Entomology, but everywhere without a name of its own. I 
have therefore attempted to publish the following description of thé insect in 
this short paper. Though I have been able to classify the insect down to its 
sub-family and genus with the aid of the valuable synoptical tables of authors 
like Ashmead, Marshall and Szepligeti, I was in some doubt as to whether it 
really belonged to the genus ‘ Microplitis’ or to one of the very closely allied 
genera ‘ Diolocogaster ’, ‘ Microgaster’, or ‘ Hygroplitis ’, and wanted to get 
my determination confirmed. Mr. H. L. Viereck of the U. S. A. Department of 
Agriculture, to whom I submitted specimens very kindly examined them and 
confirmed my identification that it belonged to the genus ‘ Microplitis’. I take 
this opportunity of expressing my thanks to this Entomologist who is a well 
known authority on the family : 
Family—Braconide. 
Sub-family—Microgasterine. 
Genus—NMicroplitis, Forster. 
Microplitis ophiuse—nov. sp. 
Colowr.—General colour shining black clothed with thin silvery pubescence which 
is more pronounced at the sides of the thorax. Head: black ; palpi fulvous ; 
face covered with very scanty silvery pubescence ; ocelli brownish; antenne : 
scape brown, flagellum dark rufescent. Thorax black ; with shining silvery hairs 
at the sides ; front legs ferruginous excepting the coxa and trochanter which are 
dark ; the tibize and tarsi of the second pair of legs ferruginous, the other joints 
dark to fuscoferruginous ; the hind legs uniformly fuscoferruginous, the tibial- 
spurs fulvous. Fore wings : smoky hyaline and irridescent, stigma dark brown, 
a fuscous cloud below the stigma and a very light infumation on the discoidals ; 
hind wings hyaline, very lightly infumated along marginal region. Abdomen : 
for a third of its length at the proximal portion both above and below, of a light 
yellowish white colour, excepting a narrow middorsal longitudinal patch which 
is shining black ; the rest of the abdomen black. 
General Structural Features.—Head : from above quadrate, almost as broad as 
thorax ; face and occiput closely and coarsely punctured ; antennz slightly longer 
