HYMENOPTERA 947 



Subfamily LEUCOSPIDIN^ 



This subfamily includes the single genus Leucospis in the Nearctic 

 Region. Our only widespread species is L. afflinis, a large black and 

 yellow chalcid frequently found on flowers. It has been bred from 

 nests of a leaf-cutter bee, Megachlle. For a revision of the species 

 see Weld: Proc. U. S. Nat. Mus. 1922, vol. 61, art. 6, 43 pages. 



Subfamily MISCOGASTERIN^ 



This group is related to the Pteromalinae. It differs in having 

 two instead of one spur on the hind tibia. Species have been bred 

 from gall insects, dipterous larva?, and other hosts. 



Subfamily PTEROMALIN^ 



This is one of the larger subfamilies of the Chalcididse. Many 

 of the species are of economic importance either as beneficial primary 

 parasites of common pests or as harmful secondary parasites. 



Pteromalus pupanmi is a common parasite of the cabbage butter- 

 fly. Oviposition is into the pupa. It is said that if a female Ptero- 

 malus finds a caterpillar of this species preparing to pupate, she will 

 wait patiently until the pupa is formed and will then oviposit into it. 

 Many Pteromalus larvae develop in a single host. In a few weeks they 

 become adults and emerge from a hole chewed in the pupal shell. 



Dibrachys bouchednus is a widespread species attacking many 

 kinds of insects. The principal requirement for a host seems to be 

 that it be enclosed in a cocoon. Since braconid and ichneumonid 

 cocoons are the ones most commonly attacked, the species is usually 

 a secondary parasite and therefore harmful. It is often reared from 

 Apanteles cocoons. After a host cocoon is located and identified with 

 the antennee, the female inserts her ovipositor and stings the enclosed 

 larva or pupa once to several times until it is paralyzed. If the host 

 is lying against the wall of the cocoon the female laps the juices that 

 flow through the ovipositor puncture. If the host is away from the 

 cocoon wall a feeding tube is constructed. To do this the female 

 parasite pushes the tip of her ovipositor just through the cocoon wall. 

 A mucilaginous substance then exudes from the tip of the ovipositor. 

 Additional quantities of this substance are occasionally added as 

 the ovipositor is slowly advanced toward the pupa. Eventually 

 there is a mucilaginous tube enclosing the ovipositor from the cocoon 

 wall to the paralyzed host. The ovipositor is withdrawn and the 

 parasite then sucks the juices of the host through the tube. When 

 she has finished feeding she seals the tube with a drop of the same 

 material and then lays several eggs on the host. The habit of making 

 a feeding tube is a common one among the Pteromalinae. 



Subfamily EULOPHIN^ 



Species of this subfamily are very numerous and mostly quite 

 small in size. They are diverse in habits and in host selection. 



