82 HETEttOMERA. \_Met(F.CUS. 



The life history of M. paradoxus will be found very fully dis- 

 cussed in the Annals and Magazine of Natural History for October, 

 1870, by Dr. Algernon Chapman, to whom I am indebted for the 

 following observations : The young larva appears to resemble the young 

 campodeiform larva of Meloe ; it is a little black hexapod, about \ mm. 

 in length, broadest about the fourth segment and tapering to a point at 

 the tail; the head is triangular with a pair of 3-jointed antennae, 

 and the legs are much like those of the larva of Meloe ; the tibiae end 

 in two or three claws, which support and are obscured by a large trans- 

 parent pulvillus or sucker of about twice their length ; each abdominal 

 segment is furnished with a very short lateral spine pointing backwards, 

 and the last segment is terminated by a large double sucker similar to 

 those of the legs ; the history of the laying of the egg and of the way 

 in which the young larva enters the wasps' nest does not appear as yet 

 to be fully understood, and, as far as I know, no wasp has been 

 observed infested by the Iarva3 of Metcecus, as the Andrence are by the 

 young Meloe larva ; we do know, however, that when the young larva 

 in the wasps' nest finds a wasp grub suited to its taste, it makes its way 

 into the interior, probably entering at the back of the second or third 

 segment ; after feeding within the larva and largely increasing in size 

 (3 to 4 mm.), it emerges from the body of its victim and casts its skin ; 

 after this it becomes shorter and thicker and loses length by the 

 curving forwards of the head, which is very marked in the full-grown 

 larva, and does not exist before its emergence from the wasp's body ; at this 

 stage the larva is found lying like a collar immediately under the head 

 of the wasp grub, and it is attached to it by the head, and appears to 

 feed upon its juices ; when it has reached a length of 6 mm. it changes 

 its skin for a second time, and gradually the whole of the wasp larva, 

 even to the head and jaws, disappears, being devoured by the voracious 

 parasite ; the perfect beetles emerge about two days after the wasps in 

 the same row of cells, and it is a curious fact that the wasps, which ap- 

 pear to investigate everything that appears unusual in the cells, with a 

 view to remove any dead pupae, are, apparently, quite as satisfied with 

 a living Metcecus larva as with one of their own pupae ; the full-grown 

 larva, as described by Dr. Chapman, is very like a Crabro or Pemphredon 

 larva ; it is of a whitish colour, much flattened, especially in front, with 

 a very small head and with the last two segments smaller than the rest, 

 the last being the smallest and apparently divided into two and 

 furnished with a very distinct rounded anal tubercle ; several of the 

 other segments are also armed with tubercles, which appear to assist in 

 holding the wasp grub ; the length is 11 mm. 



The larva of Rhipidophorus bimaculatus, F. (Emenadia larvata, Schrank.), has 

 been found in the root and stem of Eryngium campestre, which it perforates in a 

 vertical direction ; the female lays her eggs in the neck of the root, and the larva 

 hatches in March ; the insect, when full grown, works its way out of the stem about 

 the end of June, and forms a cocoon, about the size of a nut, attached to the stem, in 

 which it changes to a pupa ; the perfect insect appears in July j the habits of this 



