76 Mr. R. M‘Lachlan’s Monograph of the 
males not only differ in the number of joints from those of the 
females, but are constructed in quite a different manner. 
The following is a tabular arrangement according to the number 
of the tibial spurs :— 
Spurs 2-2-4. . . . . . « Sericostoma and Notidobia. 
Spurs 2-4-4, . . . . © » Goéra, Silo and Mormonia. 
Q- 
Spurs 2-3-3. . . . . . « Brachycentrus. 
A Continental genus (Dasystoma), species of which are very 
likely to be discovered here, has only 2-2-2 spurs. 
Genus Sericostoma, Latreille. 
Antenne shorter than the wings, the basal joint thick, shorter 
than the head. Maxillary palpi in the male broad, closing to- 
gether and forming a mask in front of the head, externally clothed 
with adpressed hairs and internally furnished with long close hairs. 
- Labial palpi long, the three joints of nearly equal length. In the 
female the maxillary palpi are very long, the basal joint very 
short; second joint longer than any of the others; third, fourth and 
fifth joints of nearly equal length; the terminal and penultimate 
joints are much thinner than the others. Labial palpi of the 
female much shorter than in the male, the joints scarcely half as 
long. Prothorax thickly clothed with hair. Mesothorax broad, 
oval, convex, sulcated in the middle above. Anterior wings long 
and narrow, the apex elliptical, costal margin nearly straight; 
hairy clothing thick and short; the radius quite straight; discoidal 
cell narrow, obliquely truncated ; the first apical cell reaches 
almost to the base of the discoidal; a transverse vein connects 
the discoidal cell with the radius, an oblique one closes the 
discoidal cell; nearly ina line with this is one closing the space 
below the discoidal, and another placed opposite the base of 
the discoidal closes the long cellula thyridii, Posterior wings 
considerably shorter than the anterior but slightly broader, also 
with a very close hairy clothing ; the discoidal cell appears to be 
open; cilia long, especially near the base of the posterior margin. 
Legs short; tibize with few very short spines; anterior and inter- 
mediate tibize with two equal apical spurs; posterior tibiee with 
two equal apical and two similar median spurs. Abdomen 
robust. In the male the app. sup. are small and obtuse, 
bandlike; the app. intermed. lie close on each side of the penis 
and are split at the extremities, the points usually differing in 
lengths; app. inf. very large, narrow at the base, the apex greatly 
dilated and notched, very hairy; penis very long and much ex- 
serted ; penis-sheaths (this term perhaps more properly belongs to 
