156 DIPTEEA. 



latter rather elongated, with microscopic hairs on the upper edge. Thoracic dorsum 

 black, brownish-pollinose, the pollen forming a pair of indistinct stripes; a yellow 

 stripe on each side, between the humerus and scutellum, interrupted above the root of 

 the wings ; antescutellar callosities, an IVI-shaped spot between them, a space in front of 

 the scutellum, and the scutellum itself, yellow ; pleurae pale greenish-yellow, with a black 

 stripe running from the collar backwards and ending under the root of the wing, and 

 another stripe immediately above the coxae (between the front and hind pairs); 

 metanotum black. Abdomen : first segment yellow, blackish at the base ; the second 

 segment black in the middle, its lateral and posterior borders reddish-yellow; the 

 following segments black, with yellow hind borders which fully reach the lateral 

 margins (the yellow occupies half the breadth of the third segment ; it is narrower on 

 the following segments, especially on the last two). Venter black, yellow at the base. 

 Halteres yellow, the knob infuscated on one side only. Front coxae yellow, this colour 

 on the other two pairs more or less mixed with black ; legs black ; on the underside of 

 the front femora, near the black trochanters, a yellow spot occupies more or less space 

 in different specimens (sometimes it invades the upperside even); middle femora 

 yellow, except the extreme base and the distal third. Wings subhyaline, with a uniform 

 pale brownish tinge ; second vein straight at the end ; second submarginal and third 

 posterior cells without any vestige of a stump of a vein. Five female specimens. 



N.B. — In the 'Linnaea Entomologica,' i. p. 383, Dr. Loew described a Phthiria 

 (belonging to the Berlin Museum) from Oaxaca, Mexico, thus : — 



"Phthiria cingulata: nigra, hypostomate, oculorum orbita, pleurarum maculis^ 

 scutello, abdominis incisuris, coxis femoribusque flavis ; alis brunnescentibus. Long, 

 corp. 2 lin." 



This applies quite well to P. consors, except the "femoribus flavis." There is a 

 specimen in the Berlin Museum which is very probably Loew's type, although it was 

 not labelled when I saw it; it differs from P. consors in having the hind femora 

 yellow, the distal fourth only being brown, while my five specimens do not show any 

 vestige of yellow on the hind femora ; it may be merely a variety of my species. 



The only other species of this genus hitherto described from our country is : — 



Phthiria thlipsomyzoides, Jaennicke, Neue exot. Dipt. p. 43, t. i. f. 11. — 

 Mexico. Jaennicke, without any necessity, introduced the new genus 

 Pcecilognathus for this species. 



GEEON. 



Geron, Meigen, Systemat. Beschr. ii. p. 223 (1820). 



This genus is represented by several specimens (in an unsatisfactory state of preser- 

 vation) from Mexico (Tuxpango and Orizaba, Sumichrast) in Professor Bellardi's 

 collection, and I have also a single specimen from Northern Sonora (Morrison). 



