Tillyard. — Studies of New Zealand Trichoptera. 347 



from the Pkryganeidae by the males having the maxillary palpi only three- 

 jointed, with the joints of normal cylindrical form, and never carrying- 

 specialized hairs or scales upon them. These also have not yet been found 

 either in Australia, New Zealand, or Africa. 



The family Sericostomatidae contains all those caddis-flies in which the 

 maxillary palps of the male are reduced to three, or sometimes even to two 

 joints, and are specialized by being of abnormal form and position, and 

 carrying either long, thick hairs or sometimes even scales. They differ, 

 too, from the Limnephilidae in having the ocelli nearly always absent. 



The Sericostomatidae are the dominant family of caddis-flies in the 

 fast-running rivers and mountain- streams of New Zealand. Our known 

 species are placed in no less than seven genera, of which five are peculiar 

 to New Zealand, one being found also in Australia, and one (Helicopsyche) 

 found everywhere except in Africa. 



In their life-histories the Phryganeidae and Limnephilidae differ from 

 the Sericostomatidae both in the general habitat of the larva and in the 

 form of its case. In the two first-named families the larva usually inhabits 

 still or slowly moving water, and the case is formed of vegetable matter. 

 A number of Limnephilidae, however, make use of other materials, such 

 as shells of small mollusca, sand, &c. These cases are always portable. 

 In the Sericostomatidae it is the exception for vegetable matter to be 

 used in forming the case, and the larvae mostly inhabit running water. 

 Most of the cases are formed of sand, or of a stiff, semitransparent chitmous 

 material secreted by the larva. Occasionally small stones or pebbles are 

 used, and much more rarely small pieces of twigs. The larvae are usually 

 gregarious, and can be found in large numbers attached to rocks, stones, 

 or sunken logs. 



The classification of the family Sericostomatidae is a most difficult 

 matter, and remains in a very unsatisfactory state, in spite of the excellent 

 work of Ulmer. A large number of genera, including those found in New 

 Zealand, are not placed in any definite subfamily or tribe, but are treated 

 as a kind of appendix to the family proper. Amongst these one may easily 

 single out the two New Zealand genera Oeconesus and Pseudoeconesus by 

 their general superficial likeness to Limnephilidae. They have the broad, 

 well-rounded wings usually found in this latter family ; whereas most of the 

 Sericostomatidae have the wings more narrowed or pointed. In life, too, 

 they resemble Limnephilidae fairly closely. The larvae form cylindrical 

 cases of small stones or pebbles, and these are usually found either singly, 

 or two or three together, attached to rocks in swiftly running streams. 

 They are very difficult to rear, as the larvae die very quickly when removed 

 from the water. 



In Mr. G. V. Hudson's collection at Karori, Wellington, there is a pair 

 of very large caddis-flies evidently closely allied to the Oeconesus group. 

 In size these are much larger than any other caddis-flies known in New 

 Zealand, the male being 1| in. in expanse, the female nearly 2 in. They 

 were taken in the Kouteburn Valley, above Lake Wakatipu. Mr. Hudson 

 very kindly allowed me to study these insects in December, 1919, when I 

 happened to be in Wellington, and I desire to thank him for giving me the 

 opportunity. The present paper is the outcome of that work, written in 

 the light of considerable further study of this difficult family. 



While on a visit to Cass, in January, 1920, I found a number of 

 very large cylindrical cases made of small pieces of beech-twigs arranged 



