242 [October, 



Carcel, vvlio fcmiid the larvre- of P. atra in rotten wood in an elm tree near 

 Paris, and is quoted by Maequart (Ins. Dipt, dii Nord dc la France— Asiliques, 

 Bombyliers, &c , &e., p. 112), eonjirlers that development lasts more than one year, 

 and probably more than two years.* Maequart (op. c(7., pp. Ill — 112) gives a 

 description of the larvte which Carcel sent liim. 



According to Zetterstedt (Dipt. Scand., VIII, p. iO*)! [l.SU)]),both sexes of 

 P. miiiKlissijiiiis {iHuiiifinsima), Ztt., were bred by Boheman between May 6th and 

 loth, 1812, from pupce found beneath the bark of old pine stumps. 



Dufour found the larvse, from whieh he subsequently bred the typical specimens 

 of P. merome/eena, in rotten wood benealh the bark of an old dead poplar in S. W. 

 France, in April, 1840, and the flies emerged towards the middle of the following 

 June. The larva and perfect insect were described by Diifour in the " Annales des 

 Sciences Naturelles," Seeonde Serie, T. XVI (1841), pp. 2(j4-2(i6, and figures of the 

 former were given in PI. 14 A, figs. 17 — 19. In his description of the larva Dufour 

 speaks by mistake of fweh-e segments behind the head, whereas in reality there are 

 but eleven ; I^ufour, however, considered the narrow margin behind the transverse 

 stigmatic furrow on the eleventh segment as representing a twelfth. 



In 1855 the species was re-described by Waidberg (Ofvers. K. Vct.-Akad. 

 Forhandl. Elfte Argangen [1854], pp. 212—213), under the name Pachygaster 

 orbitalis. Wahlberg also seems to have bred the insect fi'om larva' in poplar wood, 

 for he writes, " Hab. in ligno Populi cceso ad Gusum Ostrogoth itie." He adds, 

 " Femina pliires per annos a solstitio ffstivali ad medium mensis Augusti hand raro 

 observata, ex. gr. d. 1 Julii ad 10 Aug.. 1840; mas ignotus." The reason for the 

 latter statement, will appear subsequently. Wahlberg points out that, in addition 

 to the other ehai-acters, the species is easily distinguished by the silvery orbits from 

 the four species previously known {P. atra, Pz. ; paJlipennis, Macq. [== Leachii, 

 Curt.) ; minutissima, Ztt. ; and tarsalis, Ztt.). 



In his pa)ier, entitled, " Ilistoire des Insectcs du Pin Maritime " (Ann. Soe. 

 Ent. France, 4if--m'-' Serie, T. X [1870], pp. 135 — 232, Pis. 1—5), Perris described 

 the several stages of a species which he considered to be now, and designated Pa- 

 chygaster pini {Inc. fit., pp. 208 — 212, PI. 3, figs. 80— 88). The larva; of this species 

 were found under the bark of pine trees attacked by those of Tonticus and Hyhtrgus, 

 feeding upon the detritus and excrement left by the latter. According to Mik 

 (Verb. z.-b. Ges. Wien, Bd. XXX [1880], p. 590), Pachygaster pini, Perris, = P. 

 miniitissima, Ztt. Mik states that he bad received the species in some numbers 

 from Ilerr F. Waehtl, who bred it from the black pine {Piiius laricio, Poiret) of the 

 Vieima district in 1878. 



In concluding these notes on the life-history of the various species of Pachy- 

 gaster, it may be added that Perris {loc. cil., p. 212) states that he has bred P. 

 pallidipennis (= P. Leachii, Curt.) from larva; living in a boletus found in hollow 

 oak. 



Since Dufour's original description of P. meromelcena is very 



* In connection with Carcel's surmise that the development of Packi/pci.'^ter atra, Pz., lasts 

 longer than a year, it may be noted that according to Westwood (" Introduction," II, p. 533), a 

 larva of Clilel'laria ephippium (^ Ephippium epiiippium., Fabr. ) discovered l)y Von Roser, of 

 Stuttgart, in a rotten nut tree, "although more than half grown when found .... was 

 two years in arriving at the perfect state." 



