610 DIPTERA. 



the eyes, and the latter spotted, with yellowish white. The 

 legs are ochre-yellow, except the shanks and feet of the 



first pair, which are black. Its 



Fig. 268. . , 1,1 



body measures nearly three quar- 

 ters of an inch in length. My 

 Sphecomyia undata (Fig. 268) has 

 the slender form of a Sphex or 

 mud-wasp. It is of a light-brown 

 color, darker on the back, and 

 on the middle of the thighs and 

 shanks; its head is conical, and bears the antennae on the 

 tip of the cone ; its wings are brown on the outer part, with 

 a small transparent spot near the edge, and the inner part 

 is transparent in two large wavy spaces. It is about five 

 eighths of an inch long, and its wings expand one inch and 

 a quarter, or more. It is possible that this singular fly may 

 be the Pyrgota undata of Wiedemann. 8 An insect closely 



tillum. Pleura with an elongated yellow spot. Scutellum brassy green, metalles- 

 cent. Poitert pale ferruginous. Legs yellowish ferruginous, fore tibiae (excepting 

 the knees) and tarsi black. Hind thighs unarmed. Wings tinged with gray and 

 brown ; a pale stripe along the latter part of the cubital vein; another runs along 

 the pobrachial area and reaches the posterior margin. Abdomen yellow ; first seg- 

 ment black ; the three following segments have more or less black at the incis- 

 ures along the fore border, and a black band, attenuated at both ends, and not 

 reaching the lateral borders, in the middle; the band on the second segment is the 

 broadest, and is sometimes connected with the black of the first segment ; those of 

 the third and fourth segments are interrupted in the middle. Venter yellow, with 

 large black spots on the middle of the segments; sexual organs pale ferruginous. 



Female: shows the following differences: front yellow, with a black stripe ex- 

 tending towards the black vertex. Beside the three pairs of spots already men- 

 tioned on the thorax, there is a fourth pair in the middle of the disk, each of the 

 spots communicating by the groove with the second lateral spot. The black bands 

 on the segments of the abdomen are broader, and connect at the fore and hind 

 borders with the black incisures; the fifth segment has a similar band. The icings 

 are more tinged with ferruginous than with gray; the pale stripes less apparent. 

 B*M of thighs more or less blackish. 



I have before me two males from Illinois, collected by Mr. Kennicott, and one 

 female from Maine, collected by Mr. Packard. 



This species is very much like the European M. vespiformis, Linn. OSTEN 



K.W.] 



[ SfJteamyia undala. is the Pyrgota undata, Wied. S. valida is likewise a 

 Pyrgota, bat a new species. Myopa nigripennis, Gray, might belong to the same 

 group, as the figure in Griffith's Animal Kingdom seems to prove. OSTEN SACKEN.] 



