DIPTEEA. 



of the face, very thinly clothed with hair. Thorax reddish-yellow ; pectus black ; pile of the same colour, 

 not abundant, on the posterior part of the mesonotum more or less intermixed with black ; just in front 

 of the scutellum, in the middle, a short row of small black bristles. Scutellum a little lighter than the 

 thorax, subtranslucent ; pile chiefly black ; margin without bristles. Abdomen large, broad, yellow and 

 red ; the posterior part of the second, third, and fourth segments more or less black, the black greatest in 

 extent on tbe third segment ; anterior angles of the segments with some yellowish pile, but the dorsum 

 is altnost wholly clothed with very short recumbent black bristly hairs. Venter black posteriorly and in 

 the middle in front. Legs almost uniformly yellowish-red, the coxno black. Wings hyaline, brownish- 

 yellow along the costa and at the base ; the cross-veins of the middle clouded with black. 

 Length 16-19 millim. 



Hab. United States, Arizona 2 . — Mexico 1 2 , Temax in Northern Yucatan (Gaumer), 

 Atoyac in Vera Cruz (Schumann). 



Six specimens, including both sexes. 



This species is mentioned in my Synopsis (p. 146) as perhaps being the same as 

 V. (Temnocera) megace^hala, Loew, but I am fully satisfied that this cannot be the 

 case. Apart from the size and other striking differences, the species has neither of the 

 characters of Temnocera. In the two nortbern specimens, which are also somewhat 

 larger, the mesonotum shows indications of brown stripes, wholly wanting in the others. 

 The species is remarkable for the very large tabanoid head of the male, its very 

 small antennse, and large size. 



3. Volucella isabellina. 



Volucella isabellina, Willist. Synopsis N.-Am. Syrphidae, p. 140 \ 

 Ilab. United States, Arizona \ — Mexico, Northern Sonora (Morrison). 



A single specimen from Sonora agrees well with the description, but is somewhat 

 smaller than the size there given. 



4. Volucella quadrata, sp, n., $ . (Tab. I. figg. 12, $ ; 12 a, head; 12 b, an- 

 tenna.) 



Allied to V. decora, V. castanea, V. lata, &c. Headlight yellow, a brown band at the upper part of the front, 

 and a similarly coloured stripe on the cheeks ; front broad. Pace in profile gently receding, forming a 

 long, moderate convexity, not tuberculate or concave, produced downward but little. Pile of the frout 

 blackish, that of the face light yellow, short. Proboscis black, short. Antonnse very small, red ; third 

 joint gently widened at the base, and briefly emarginate before the tip ; ariata thinly plumose. Meso- 

 notum dark brown, with two faint pollinose stripes in front ; the kteral margins, and a large quadrate 

 spot behind, light yellow ; pile moderately abundant, yellow. Pleurae hlack, a large light yellow spot 

 on the mcsopleurae, covered with dense yellow pile. Scutellum translucent reddish-yellow, without 

 bristles. Abdomen yellow and red, with the posterior part of the segmenta black ; covered with short 

 recumbent black hair. Lega brown or blackish-brown, the knees and the base of tibias somewhat lighter. 

 "Wings nearly as in V. esuriens ; a dark brown subquadrate spot at the middle in front, hyaline beyond, 

 and brownish on the basal part. 



Length 14 miilim. 



Hab. Mexico, Chilpancingo in Guerrero (H. II. Smitli). 

 One specimen. 



