PSYCHE. 



THE PRIMITIVE NUMBER OF MALPIGHIAN VESSELS IN 



INSECTS. — VI. 



BY WILLIAM MORTON WHEELER, PH.D., CHICAGO, ILL. 



Hymenoptera. According to Schind- the wall-bee (Chalicodoma muraria) . 

 ler the number of Malpighian * ves- This number is retained during larval 

 sels in the imagines of Hymenoptera life, as has long been known (see 

 varies from 1 2 to upwards of 150. The Leuckart's figure in Lang's Verglei- 

 number 12 was observed in Myrmica, chende anatomie, p. 476). According 

 the greater number in Apis.f In cer- to Carriere the Malpighian vessels of 

 tain ants according to Adlerz \ a very Chalicodoma arise as two pairs of in- 

 small number is observed, the neuter vaginations on the caudal plate (which 

 of Tomognathus having only 6 vessels. is an extension of the ectoderm behind 

 Embryology shows conclusively that the eleventh abdominal segment). In 

 none of these numbers (excepting per- his first account they are said to arise 

 haps that of Tomognathus) are to be "ehe die einsenkung des hinterdarmes 

 regarded as primitive. Biitschli§ found beginnt; ihre miindung wiichst mit 

 onlv 4 vessels in the embryo of the dem boden bez. dem rande des hinter- 

 honey-bee {Apis mellifica) and darmes nach dem hinterende des mit- 

 Carriere|| gives the same number for teldarmes zu." 



Adlerz* claims that the larvae of 



* 1. c. P . 6 3S et seq. ants have 4 Malpighian vessels. It is 



tThe numbers given by Schindler run as follows more than probable that til IS is the 



number formed in the embryo. 



It appears that we have no cases 

 among Hymenoptera with 6 Malpighian 

 vessels in the embryo and only 4 in the 

 larva. On the supposition that 6 is the 

 original number we must therefore con- 

 clude that a pair of tubules has been sup- 

 pressed in the ancestral Hymenoptera. 

 It must, however, be borne in mind 

 that we have no observations on the 

 embryonic development of the excretory 



• I.e. 



Formicidae. 



Myrmica 12. 



Formica fiibescens 25-30. 



Formica rufa 16. 

 (Adlerz gives 20 for F. ntja and Camponotus.) 

 Ichneumonidae . 



Microgaster 15 (Dufour). 



Chelonus, more than 20 (Dufour). 



Ophion merdarius, about 40. 



Some other Ichneumonids more than 40. 

 Cvnipidae, at most 20-25. 

 Chrysididae, about 100. 

 Crahronidae, ) 



Vesflidae, \ more than 100. 



Apidae, ) 



X Myrmecologiska studier. 2. Svenska myror och 

 deras lefnadsfurhollanden. Bill, svenska. vet. akad: 

 handl. bd. 11, no. iS. 1SS7. 

 §1. c. 



|| Die entwicklung der maurbiene (Chalicodoma 

 muraria, Fabr.; im ei. Arch. f. mikr. ar.at. bd. 35, 

 heft 2, 1S00. 



