1913] Pinhus — History and Habits of Spalangia Musculorum 151 



Copulation takes place very shortly after emergence. The males 

 are ever ready for mating. They seize the females and cling to 

 their backs, caressing them with their antennae for some time 

 until the female exposes the ovipositor and copulation takes place. 

 This act has been observed to take place a number of times at short 

 intervals. Often two or three males endeavor to secure the atten- 

 tions of the female at the same time. 



Oviposition. 



Spalangia muscidarum is a simple parasite 1 and does not usually 

 deposit a second time in a single host. When a female finds a pupa 

 she first makes a thorough examination with the antenna? and then 

 fixes herself firmly on the pupa. She then begins to feel about on 

 the pupa with the tip of the ovipositor, sometimes changing her 

 position if the first spot attacked is too hard for penetration. The 

 ovipositor is usually inserted near the cephalic end of the puparium, 

 generally on a suture. While ovipositing, the female is not easily 

 disturbed. In some cases the puparium may roll over and yet 

 the parasite retains her position. The accompanying figure 

 (Plate I fig. 1.) of the female in act of depositing was drawn from 

 a photograph taken by Mr. H. P. Wood. About ten or fifteen 

 minutes are required for the deposition of an egg. 



Repeated efforts to induce the female to deposit an egg in a 

 puparium which had already been deposited in were unsuccessful. 

 In every case the female quickly recognized the fact that the pu- 

 parium had already been attacked, and left it in search of other 

 hosts. A female which was supplied with fresh pupae as fast as 

 oviposition took place was observed to deposit in fifteen different 

 pupae in succession. She would have, undoubtedly, deposited in 

 many more pupae had they been supplied, as she appeared strong 

 and active after having laid these eggs. Subsequent examination 

 of these fifteen puparia showed that immature parasites were 

 developing in four and all of the others were dead, probably as the 

 result of the insertion of the ovipositor. When numbers of puparia 

 were supplied to parasites in cages, in only one case did an adult 

 fly emerge, the others having succumbed to the attack of the 

 parasites. 



1 Pierce: On some phases of parasitism displayed by insect enemies of weevils. Journ. Econ. 

 Ent., vol. 3, p. 452, 1910. 



