the aquatic forms mentioned above may be obtained for breeding by the use of the dip net by dragging it forcibly against water plants. [Illustration: FIG. 85.--_b_, a May-fly (_Palingenia bilineata_); _c_, its larva; _a_, a Caddis-fly (_Macronema zebratum_).] [Illustration: FIG. 86.--A Dragon-fly (_Libellula_). (From Packard.)] [Illustration: FIG. 87.--A Dragon-fly (_Agrion_). (From Packard.)] _Neuroptera proper_ (Hellgrammites, Lace-wings, Ant-lions, Caddis-flies, etc.)--Among the largest insects of this order are the Sialidae, which includes the enormous Hellgrammite Fly, _Corydalus cornutus_. The larvae of this insect are carnivorous and occur in streams, under stones, etc. The adults may be collected in neighboring situations and are also attracted to light. The Lace-wing flies (_Chrysopa_), Ant-lions, etc., are carnivorous as larvae, and occur, the former among the Aphides which infest various plants and the latter at the bottom of pits in loose, sandy soil. The adults may be obtained by general sweeping and are also attracted to light. The most interesting insects of this order are the Caddis-flies, on account of the peculiar and frequently very beautiful cases constructed by their larvae, which it is important to collect. The Caddis-flies breed in ponds and lakes and the adults may be collected in such situations or at light. The larvae may easily be reared, and should be collected for this purpose. Most of the insects named in this order are extremely delicate and require great care in handling. [Illustration: FIG. 88.--An Ant-lion, adult (_Myrmeleon_). (From Packard.)] KILLING AND PRESERVING INSECTS. Between the collecting of the specimens and their final disposition in a well-arranged cabinet, a good deal of mechanical work is necessary, involving a skill and dexterity which can be thoroughly acquired only by practice.