(tlO DIPTERA. 



tlic eyes, and the latter spotted, -vvitli ycllowisli Avliite. The 

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



fu'st pair, which arc Mack. Its 

 Lody nieasui'cs nearly tlirce quar- 

 ters of an inch in length. My 

 Sfliecomyia vndata (Fig. 2G8) has 

 the slender form of a Sphex or 

 mnd-Avasp. 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 Pijrgota undata of Wiedemann.^ An insect closely 



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

 cent. Poisers pale ferruginous. Ler/s yellowish ferruginous, fore tibice (excepting 

 the knees) and tarsi black. JTind thif/hs 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 foi-e 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 j^ellow, with 

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



Female: shows the following differences : //-oHi 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 wings 

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

 Base 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 

 Sacken.] 



[ 8 Sphecomyia undata is the Pyrgota undata, Wied. S. valida is likewise a 

 Pyrgota, but a new species. Mijopn nigripennis, Gray, might belong to the same 

 group, as the figure in Griffith's Animal Kingdom seems to prove. — Osten Sacken.] 



