HARDWICKE'S SCIENCE-GOSSIP. 



37 



flying seldom, and then but heavily, and only for 

 short distances, the wings, especially those of the 

 males (which are usually very short, and in some 

 species reduced to mere rudiments), being of little use 

 for purposes of aerial locomotion. The female, after 

 coupling, deposits her eggs, which remain for a time 

 attached to the end of her abdomen, in stagnant or 

 running water, this being according to the predeter- 

 mined habits of the species. She then, together with 

 the male, does not survive the commencement of the 

 new developmental cycle entered upon by the 

 extruded ova. 



Now, as to collecting. Search should be made for 

 the larvae and pups with a water-net — at weir-heads 



Fig. i5. — Perla maxima. 



Fig/:7. — Chloroperla grammafica. 



Fig. iS. — Dictyopteryx microcephala. 



and slight falls of water where the flow is rapid, on 

 stones by the water-side, and in any place that may 

 suggest itself to the collector as a likely haunt for 

 these insects. The imagines may be readily captured 

 both whilst in flight, and when at rest on the ground 

 or on palings, or trunks of trees in the immediate 

 vicinity of the water in which the previous portion 

 of their existence was passed. Beating, as for Coleop- 

 tera, may also be employed, with every chance of 

 making captures. 



A few words on rearing and preservation. The 

 majority of the Perlina are difficult to rear in captivity, 

 as many of the insects in their earlier states require a 

 constant supply of running water. Some species of 

 Xemourinae may, however, be bred through in an 



ordinary aquarium, or failing that, in a jar, provided 

 there be a plentiful store of suitable food. 



Larvae and pups may be preserved for the cabinet in 

 phials or test-tubes filled either with pure or carbo- 

 lized glycerine, or the microscopist's mounting 

 medium known as " Goadby's Fluid," as this mode 

 of treatment prevents the alteration of form and 

 colour so prevalent when these larva? are allowed 

 to dry. Kerosene and benzoline are also useful pre- 

 servatives. I do not advocate the use of spirits of 

 wine, as by it the delicate colours of the insects are 

 modified or entirely destroyed, though the form 

 remains unaltered. As regards the perfect insects, 

 the ordinary modes of preservation may be adhered 



Fig. ig.—Isogemis nubecula. 



Fig. 20. — Isopteryx tripuuctata. 



Fig. 21. — Capuia jtr'gra. 



Fig. 22. — T&niopteryx nebulosa. 



Fig. 23. — Nemonra va-riegata. 



Fig. 24. — Lencira fusciventris. 



to. Some specimens of each species should, however, 

 be put up in phials filled with glycerine or other pre- 

 servative fluid, to prevent as much as possible the 

 fading of the colours. A supply of test-tubes should 

 be taken to the collecting-ground, so that individuals 

 of each species may be placed in fluid as soon as they 

 are captured. 



In labelling these tubes, it is advisable to prepare 

 two labels, bearing parallel information relating to 

 name, date, and place of capture, etc. One of these 

 labels should be attached to the outside of the tube, 

 and the other enclosed with the specimens. 



All pinned specimens intended for the cabinet 

 should be set as soon as possible after capture. The 

 wings of some species, if allowed to become dry, cling 



