6 Mr. R. M‘Lachlan’s Monograph of the 
Characters of the Families. 
These divisions are most readily separated according to the 
number of joints in the maxillary palpi of the males ; thus — 
A. Not more than four joints . . Herrrorarporpea, Kolenati 
(1848) InaqQuipaLPips, 
Kolenati (1859). 
@ Jomtsifour ). 5.9. ~ «= . bunycanma. 
aa Joints three. . . . . . « Limnephilide. 
aaa Joints two or three, differing 
greatly in structure from those 
ofthe females . . . . . Sericostomide. 
aaaa Joints four. Insects minute and 
very hairy . . . . . © Hydroptilide. 
B. Five joints (similar to those 
ofthe female) . . . . Isopanporpea, Kolenati (1848) = 
JEquipatpip#, Kolenati (1859). 
6 Palpi very hairy; terminal joint 
flexible but simple. . . . . Leptoceride. 
bb Palpi as a rule slightly hairy; 
terminal joint very long and 
multiarticulate . . . . . «. Hydropsychide. 
bbb Palpi usually scarcely hairy; ter- 
minal joint cylindrical . . . Rhyacophilide. 
The larvee of the first five families live in portable cases ; those 
of the other two, either free under stones, or in fixed cases. 
For more detailed characters, see those given under each family, 
remembering that these strictly apply only to British, or at any 
rate to European, forms. 
Generic characters. 
There is probably no subject on which more difference of 
opinion exists than that of genera, owing to these divisions being in 
reality man’s invention for his own convenience, but nevertheless 
indispensably necessary. 
To a beginner in the study of the T'richoptera I would beg to 
offer the following hints on this subject. Being satisfied as to the 
family to which an insect under examination pertains, first ascer- 
tain the number of the tibial spurs, as it is a recognized rule that 
all the species of a genus should agree in this respect. The form 
and proportions of the joints of the palpi should be next consulted. 
Then the arrangement of the nervures of the wings* should be 
* See the “Index wings” in Plate III. fig. 5, where the nervural nomen- 
clature is explained. It must be remembered that although, as a rule, the 
