38 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



pupa a little before its maturity one perceives that the front is still 

 entirely soft; one even sees that the animal, disturbed in its repose 

 and wishing to escape, strongly inflates its frontal region and causes 

 a small bladder to come forth. By a violent effort the bladder be- 

 comes inflated, and, pressing upon the anterior part of the pupa, a 

 faint, sharp report can be heard. A small anterior piece, correspond- 

 ing to the upper part of the head and the two upper dorsal segments, 

 is propelled forward, often several centimeters, the upper zonite 

 bearing the [stigmatal] horns is raised, and the Volucella appears. 1 



Kiiuckel d'Herculais points out that the ptilinuin has a fur- 

 ther function. After the front of the puparium has been 

 forced off, the fly, in order to pass the narrow orifice of its 

 prison, diminishes the volume of its thorax and abdomen by 

 forcing the blood into the head. Reissig, much before this, 

 had already shown that newly emerged Tachinidee use the 

 ptilinum to push obstacles out of their way. 



L/ovvne makes the remarkable assertion that "Kiiuckel d'Her- 

 culais says there is no frontal sac in Volucella or the Syr- 

 phidse," which leads us to the assumption that he did not 

 know the French investigator's remarkable work at first hand. 2 



Becher, on the other hand, disputes Kiinckel d'Herculais 

 on the opposite grounds. He asserts that Kiinckel d'Hercu- 

 lais is in error and that there is no frontal bladder in the Syr- 

 phidse, nor in Platypezidse and Pipunculidse. In fact, on this 

 basis, he indicates a group for these families and the Phoridse, 

 calling them Aschiza, and designating the remaining Cyclor- 

 rhapha as the Schizophora. Before Kiinckel d'Herculais, 

 Gerstaecker had already announced the presence of a frontal 

 bladder in Eristalis, and he is quoted to that effect and dis- 

 puted by Becher. The passage is from Gerstaecker's review 

 of Brauer's "Monographic der Oestriden," and, translated, 

 reads as follows: 



That the Syrphidae, in which the author has up to now missed the 

 frontal bladder, possess such, maybe frequently and easily established 

 in the autumn on newly emerged specimens of Eristalis tenax. 3 



Becher based his assertions virtually on a study of the mature 

 imago, as is apparent from the following statement: 



Because the frontal bladder never disappears without leaving a 

 trace in the mature insect, but remains within the frontal suture as 



'L. c., p. 77. 



'-'The Anatomy, Physiology, Morphology, and Development of the 

 Blow-fly, vol. 1, pp. 125-126 (1892). 



3 Bericht iiber die wissensch. Leistungen im Gebiete d. En torn., 

 1863-18<>4, p. 395 (1867). 



