A CHALCID PARASITE OF ENDOMYCHUS COCCINEUS, LINN. 9U 



was brought home, and on June 16th one was noticed just 

 becoming adult. The elytra were then of a very beautiful pearly 

 shell-pink colour with no trace of spots, the thorax and abdomen 

 a deep salmon-pink with almost an orange tint and the legs and 

 antennae brown. Later in the evening the posterior spots on 

 the elytra were faintly indicated by darker areas, and by the 

 next morning all four dark spots were well marked, the ground- 

 colour of the elytra remaining pink, while the thorax had 

 deepened somewhat in colour. During the following days 

 many more specimens became adult, though the final deep 

 red colour of the elytra only developed very slowly, and it was 

 not until July 3rd that the majority had assumed the typical 

 appearance of Endomychus coccineus. During this period and 

 for some long time afterwards the beetles showed no disposition 

 to leave the fungus. 



When first taken all the pupae were alike in appearance so 

 far as was observed, but about June 16th it was noticed that in 

 a number of cases development was apparently not proceeding 

 normally. Some of the pupas had turned dark brown, the outer 

 skin becoming harder and more chitinous and the abdomen 

 completely changing in shajje, becoming curiously elongated, 

 narrower and cylindrical. Parasitism was suspected and these 

 brown pujpae were isolated and kept under observation. 



No further change was observed until July 11th (some days 

 after all the healthy pupa; had become adult), when one or two 

 were found to have small round holes in the back and a number 

 of Chalcids were found in the box. On making a hole in another 

 from which the parasites had not yet emerged, six of the parasites 

 immediately crawled out and hopped about apparently fully 

 developed. There was still a good deal of fluid in this pupa 

 case. The flies were packed in the anterior two-thirds. During 

 the next few days the parasites emerged from the remaining 

 pupse, and of ten cases in which the number of flies hatching 

 from a single pupa was noted, eight produced 5 $ 2 and 1 (? 

 each (the c? much smaller than the 2 2), one produced 6 2 2 

 and 1 $ , and one 5 2 2 only. Of the total number of 65 pupae 

 originally taken, 'J5 became adult beetles, 26 were known to be 

 parasitised and the remainder died or were killed at an early 

 stage. 



With regard to the identity of the Chalcid, the following 

 reference to a parasite of Endomychns coccineus, which occurs in 

 Curtis' description of this beetle (' British Entomology,' vol. ii, 

 p. 570), is of interest : " Neither Latreille nor any author that 

 I can remember has characterised the larvae of EndomycJius, 

 and having found a considerable number. ... I shall 

 proceed to their description and history. In pulling the bark 

 oft' the decayed stump of a fir-tree I saw some larvae apparently 

 entangled in a white cottony web, which I at first thought were 



