Die morphologischen Merkmale und die Bionomie der Kiefernspanner‐Tachine Carcelia obesa Zett. (= rutilla B. B.)

Summary1 The Tachinid Carcelia obesa Zett. (= rutilla B. B.) is in Holland an important parasite of the pine looper ( Bupalus piniarius L.), a pine wood inhabiting geometrid moth. 2 As an introduction to future papers on the function of the parasitic fly as a mortality factor to the moth, the most important data on its external morphology and life history are represented here. 3 The most important characteristics of the adult fly can be found by Baer (1920/1921). See also fig. 1. The female parasite bears on her relatively broad forehead two large hairs curved downwards, which are lacking in the male. 4 The egg has the macrotype form (Clausen 1940) with its ventral surface flat and the chorion thin and transparent. Its surface bears rather minute reticulate markings. 5 The most important characteristics of the three larval instars have been described (fig. 2, 3, 4 and 5). 6 The puparium is of the general subelliptical form. The anal opening and the anterior and posterior spiracles are distinct. Prothoracic cornicles are present. There are two lines of cleavage. 7 The adult fly emerges from the puparium in June—July; the males 6 days before the females in average. Mating normaly takes place very soon after emergence. 8 After mating the fertilized eggs descend into the uterus where incubation takes place over a period of three weeks in average. Then the larvae can be observed through the transparent egg chorion. 9 The incubated eggs are deposited on the skin of the caterpillers, which at the time are in the second and third instar. There within 2–24 hours the larva bores directly downward through chorion on the vertral side of the egg and through the integument of the host body. Most often the young larvae enter the wall of the foremost part of the intestine; afterwards they enter a muscle. They have a cutaneous respiration. 10 Hibernation takes place in the host puparium without apparent growth. The latter begins at the end of March and soon afterwards the first molt takes place. 11 After the second molt in April—May the third instar larva is full grown within 25 days and emergence is usually effected from the wing pads of the host pupa. The larva pupate outside the hostbody in the litter. The duration of the pupal stage is about 4 weeks in average.