218 



MR. A. M. ALTSON ON THE LIFE-HISTORY AND 



are sometimes found with living ones, but nsually all are dearl. 

 The dead larva is always discoloured and appears to have shrunk 

 to the size of the meconium, so that they are then quite hard. 



The number of larval instars have not been worked out, but 

 the general ap])earance of the larvse is constant. The larva 

 (text-figure 14) is a typical vermiform hymenopteron, broadest in 

 the centre and tapering towards the extremities. It consists of 

 apparently 14 segments. It has nine consecutive pairs of 



Text-figure 14. 



Full-grown larva of -N". ftret>icor?iJS. X25. Orig-inal. 



spiracles, of a very simple structure, on 2nd and 3rd thoracic 

 and 1st to 7tli a.bdominal segments. The integument is smooth, 

 glabrous, very thin and easily damaged; it appears to secrete 

 some sticky fluid which entirely bathes the integument, and 

 which enables it to "• grip " the surface over which it is moving. 

 An examination of the larval integument discloses minute pores 

 scattered about the surface and presumably the source of this 

 ''sticky" fluid. Larvae have been frequently found in a puparium 

 from wdiich a number of adults have emerged with portions of 

 pupal exuvia attached, sometimes completely covered with it. 

 The mid-intestine is closed caudally during the entire larval 

 development, and the waste matter within it is brown. This 

 gives the larv-a a dirty white appearance. The slightest puncture 

 made in an active larva about the centi e of its body will cause the 

 contents of the intestine to exude instantly, leaving the larva 

 white. The period of development of the larvse occupies about 

 7-10 days from the time of hatching, w^ith a pro-pupal stage of 

 1-3 days. 



A few hours before casting its last larval exuvium, the contents 

 of the mid-intestine is voided. This appears to indicate that the 

 mesenteron and proctodeum become connected before the pupa is 

 formed. "The meconial discharges of this parasite, found 

 scattered through the host puparium, are brownish yellow or 

 dark olive-green in colour, and consist of small conglomerations of 

 round pellets, or are sometimes in irregular chains, like some 

 bacteria, but are never single, solid pieces " (6). 



The length of larval life is very variable. 



The Fupa. — After voiding the meconium the larva remains 

 motionless — unless disturbed by a fellow-occupant of the host 



