Linnean Society. 4175 



from this penetrates into the abdomen of its victim, and there continues to feed until 

 it is full-grown ; which is not until some days, and sometimes even weeks, after the 

 earwig has assumed the imago state. The larva then escapes by forcing itself between 

 the segments of the earwig's body, and the victim, already rendered sterile, soon dies. 

 The larva at first moves about very quickly, but soon becomes quiet and changes to 

 the pupa condition, usually within a couple of hours. When this state is assumed 

 during the summer, or in the early part of the autumn, the fly is produced in about a 

 fortnight or three weeks, according to the temperature of the season ; but when the 

 earwig's body is not left until late in the autumn, the pupa remains through the win- 

 ter in the earth, and the fly makes its appearance in the spring ; and this also is the 

 case when the larva remains in the earwig's body during winter, and assumes its pupa 

 condition in the spring or early part of summer. The body of the larva is about three- 

 tenths of an inch in length, is soft, white, and tapers anteriorly to a very small but 

 distinct head, which is furnished with a pair of retractile hooks. The body is formed 

 of twelve distinct segments, including the head, and posteriorly has two projecting, 

 corneous, black, tubular breathing-organs. The pupa is oval, smooth, and of a dark 

 brown colour, and retains the breathing-organs of the larva projecting obliquely out- 

 wards on either side, at its posterior extremity. The imago fly appears referrible to 

 the Metopia of Meigen, and the author proposes to designate it Metopia Forficulee, 

 and to distinguish it as follows : — 



" Genus Metopia, Meigen. 

 " Metopia. Forficulse, cinerea, oculis testaceis, antennis nigris, corpore pedibus- 



que pilis longis nigris vestitis ; thoracis pilis lineas 6 longitudinales efforman- 



tibus, scutello alarum basi femoribusque ferrugineis. 

 *' Mused, domesticd aliquanto minor ; Forficulas prope Londinam infestat." 



Parasite of the Emperor Moth. 

 The author also exhibited specimens of another parasite of the same family, Exo- 

 rista larvarum, which he had bred from pupae of the Emperor moth, (Saturnia Pavonia 

 minor). This species is constantly seen in the early part of summer, in the hot sun- 

 shine, on hawthorn hedges, when the larvae of Pavonia are feeding. It appears to be 

 the common parasite of the Emperor moth, in one cocoon of which were the dead pu- 

 pa of the moth, together with ten living pupae of the fly. In other cocoons there were 

 nine, seven, six, four, thiee, and two respectively, and in one instance only a single 

 parasite. The pupa of the moth, in each instance, had been perforated by the para- 

 sites, which thus appear to effect their escape into the cocoon, in the larva state, and 

 then into pupae ; as is the case with the Hymenopterous larva of Ophion luteum 

 which infests the puss moth. The pupa of this parasite on Pavonia differs from that 

 of the earwig in its surface retaining distinct roughened annular indications of the 

 twelve segments of the body of the larva, and also in the breathing-organs being 

 marked by three slight protuberances on each side, at the posterior extremity, above 

 the anus. 



Cocoons of the Emperor Moth. 

 Mr. Newport also described and exhibited two remarkable cocoons of the Emperor 

 moth. One of these had two perfect outlets, but in other respects was a single cocoon, 

 and had contained only one pupa, from which the moth had been developed. The 



