Miscellaneous. 75 



pupal stage ; after the lapse of from eight to ten days the pupae 

 produced specimens of Sarcophaga clathrata, Meigen *. 



This Muscid is widely distributed in Algeria : I have hred it 

 from larvae derived from Stauronotus maroccanus as well as from 

 Acridium aegyptiwm and other indigenous species ; but it is not the 

 only Sarcophagid which in that country may be parasitic upon 

 Acridians ; from specimens of Stauronotus I have observed larvae 

 emerge which have developed into Sarcophaga atropos, Meigen, 

 S. eruentata, Meigen, and S. nurus, llondaui ; and from migratory 

 locusts larvae which have produced S. (Agria) affirm, Fallen, and 

 likewise S. nurus, llondaui f ; this latter is, moreover, a common 

 species. 



The larvae of the parasitic species of Sarcophaga are admirably 

 adapted for passing their existence in the body-cavities of their 

 hosts, and differ in a remarkable manner from those which live in 

 the open air in dead bodies — from those of S. camaria, L., for 

 example ; they have neither the form nor the external aspect of 

 common maggots J ; the posterior stigmata, which are situated 

 upon the last ring of the abdomen, are placed at the bottom of a 

 cavity, which can be closed more or less completely by means of an 

 upper and two lower lips ; they are composed, in larvae which have 

 attained their full size, of three pairs of oblique clefts. The arrange- 

 ment of the external organs of respiration is in itself alone sufficiently 

 characteristic to justify the separation of the parasitic Sarcophagids 

 from their congeners. 



The habits of the adult insects are no less specialized. The vivi- 

 parous flies follow the bands of locusts, which they harass unceas- 

 ingly. If we possess the requisite patience we may sometimes 

 surprise a female in the act of inserting her curved oviduct between 

 the anal plates of the victim, which she has selected in order to 

 deposit thereon a tiny larva, girdled with several rows of spinules, 

 which will be able to open a passage for itself in order to penetrate 

 the body of the insect which is destined to harbour it. 



This parasitism, owing to its physiological consequences, is of the 

 first importance, for in the case of the locusts it destroys the power 

 of aerial locomotion aud suppresses the reproductive faculty, By 

 absorbing for their own respiration the oxygen dissolved in the 

 sanguineous plasma of their host, and by devouring the adipose 

 tissue from which the latter has to derive the constructive principles 

 of the organic elements of new formation, the larvae of the Sarco- 

 phaga are the cause of a general insufficiency of nutriment for 

 the tissues ; they smite with impotence the elevator and depressor 



* Bull, de la Soc. d'Agr. d'Alger, 34 e annee : Bull. no. 103, 1891, p. 47 

 (seance du 15 mai, 1891). Uepeche alyerienne, no. 2111, 19 mai, 1891. 



t A preliminary determination of the species was made according to 

 the types of Meigen and Macquart, preserved in the collections of the 

 Museum ; a second and independent determination, which served to 

 control the former, was solicited from Dr. R. II. Meade, of Bradford, who 

 is so widely known for his knowledge of the Muscidae, and to whom I 

 here convey my best thanks. Cf. J. Kiinckel d'ilerculais, ' Les invasions 

 des Acridiens, vulgo Sauterelles, en Algerie,' pi. i. S. clathrata, larva and 

 adult, tigs. 20-22; 8. nurus, fig. 23; 8. uffinis, fig. 24. 



\ Loc. cit. pi. i. fig. 20, a, b, and c. 



