38 Psyche [February 



AN UNDESCRIBED HYMENOPTEROUS PARASITE OF 

 THE HOUSEFLY. 1 



By C. H. Richardson, Jr. 



During the summer of 1912, Mr. J. H. Paine reared from the 

 pupa? of Musca domestica Linn, at Forest Hills, Mass., a number 

 of specimens of an apparently undescribed Pteromalid belonging 

 to the genus Spalangia. These were kindly placed at the writer's 

 disposal and formed the basis of a life-history study which, it is 

 hoped, will be published in the near future. 



The present paper deals with a preliminary description of the 

 species which will be known as 



Spalangia muscidarum sp. nov. 



Male: (Fig. 1) Length 3-3.5 mm. Frontal aspect of head oblong-ovate, with 

 numerous large depressions; eyes ovate, not emarginate in front; entire head 

 covered with a short rather stout light-colored pile; ocelli present; labrum very 

 small in proportion to length of head, the free border rounded, hairy; mandibles 

 bidentate, length more than twice the width at base; antennae 10-jointed; scape 

 as long as the three, succeeding joints, covered with hair of the same texture as that 

 on the head, second joint shortest; third joint almost as long as the succeeding two; 

 the remaining seven joints except the last which is longer, of equal length; they are 

 covered with fine light-colored hair; gense punctate like the face. 



Thorax above with the three divisions distinct; anterior narrowed portion of 

 pronotum finely punctate and sharply marked off from the posterior part, which is 

 sparsely and very coarsely punctate except for a median smooth space widest 

 posteriorly; a transverse row of deep umbilicate punctures near its posterior margin; 

 mesonotum smooth and polished anteriorly, sparsely punctate posteriorly and 

 laterally leaving a smooth median space for its entire length; parapsides prominent 

 with a few scattered punctures; parapsidal grooves deep, punctate; scutellum 

 smooth, sometimes with several scattered punctures at sides; a distinct puntured line 

 crosses it posteriorliy; post-scutellum smooth; metanotum with two deeply punctate 

 longitudinal lines separated by a smooth raised area; on either of these lines of 

 punctures is a smooth space bounded posteriorly and laterally by numerous deep 

 punctures, smallest and most abundant on the sides. Mesopleurse each with a 

 single fovea; an aciculate depression below and behind the tegula. Abdomen 

 smooth except petiole which is finely aciculate; 3rd segment largest. Hind coxa? 

 swollen; first joint of tarsi not quite as long as the succeeding four. Wings hyaline 

 covered with short stout hairs. Venation piceous. Color of thorax deep bronze; 

 abdomen deneous; the tarsi yellow-brown except the last joint which is black. 



The female is larger and of a more delicate structure than the male. The head is 

 longer and narrower (Figs. 3 & 4), the antenna; are more slender and the abdomen 

 (Fig. 2) is of different proportions. 



i Contributions from the Entomological Laboratory of the Bussey Institution, Harvard 

 University, No. 64. 



