June, 1903.] Society of the S^gma Xi. 451 



Jassidae, all of which have active jumping habits. Hence, this 

 peculiar chela may have been developed for the special purpose of 

 holding to the host larva while an egg is being deposited. 



EXP1.ANAT10N OF Plate 20. 



Fig. I — Nymph of Onnenisseptentrionalis, showing the sack in which the 

 larva of Dryinns ormenidis lives, protruding from beneath the right wing 

 pads, X5. Fig. 2 — Cocoon of D. ormenidis; a, the flatter portion of it ; b, 

 the more convex portion which contains the pupa ; c, exuvia of n^'mph of 

 O. septentrionalis ; d, the empty sack from which the Dryinus larva has 

 escaped, X5. Fig. 3— Leaf upon which there are three cocoons; a and r, 

 cocoons of D. ormenidis, surmounted by exuvite ; l\ cocoon of L,abeo tj-ph- 

 locybae, surmounted by larval sack, natural size. Fig. 4-S — Dryinus ormeni- 

 dis. Fig. 4 — Larva, x 10 ; Fig. 5 — Ventral view of pupa, x 10 ; Fig. 6 — adult 

 female, xio; Fig. 7 — tarsus of fore leg ; a, antennal brush, or comb on the 

 first segment of tarsus ; h, tibial spur which holds the antenna against the 

 comb while being cleaned ; c\ peculiarly modified 5th tarsal segment, X37. 

 Fig. 8 — Tarsus partly flexed at 1)ase to show how the spur comes into apposi- 

 tion and works with the antennal comb, x 37. 



ExPLAN.\TiON OF Plate 21. 



Fig. I — Adplt male of Labeo typhlocybse, x 10. Fig. la — Forewing of L. 

 typhlocybte, showing venation as it appeared shortly after transformation, 

 X 10. Fig. 2 — Ventral view of pupa of L. typhlocybte, x 10. Figs. 3-10 — 

 Cheiloneurus swezeyi : Figs. 3-4— Adult female, x 10 ; Figs. 5-6 — ventral and 

 dorsal views of pupa, x 10 ; Fig. 7 — antenna, x 50 ; Fig. 8 — fore leg, at a, 

 antennal conil), X50 ; Figs. 9-10 — tibia and tarsus of second and third legs, 

 b, movable spur, x 50 ; Fig 11 — female Gonatopus bicolor, x 10. Fig. 12 — 

 male Labeo longitarsis, x 10. Fig. 13— nymph of Liburnia lutulenta with 

 parasitic larva in sack on its abdomen, x 10. Fig. 14 — fore-tarsus of female 

 Gonatopus bicolor, x 40. 



THE SOCIETY OF THE SIGMA XI. 



Among Greek letter societies the one which is of especial 

 interest to students of science is the Society of the Sigma XI. 

 Its badge is now .seen so frequently at meetings of scientific men 

 that it is well to know exactly what it stands for. In 1886 at 

 Cornell University the first chapter was founded and the initial 

 letters of the phrase meaning ' ' companions in zealous research ' ' 

 made the name of the society. Since this beginning it has grown 

 especialh- during the last few 5'ears until now nearly e\-er3' large 

 university in the country has a chapter, the most recent additions 

 being Chicago and Michigan. 



It is an honor society open to men and women who have 

 distinguished them.selves in scientific or technical work. By the 

 constitution two .standards are set up : one relating to the eligi- 

 bility of members of a college or university faculty and to alunuii 

 and one to students in the fourth 3-ear class. The first standard 

 calls for an actual contribution to science and the second for such 

 scholarship and success in scientific or technical studies as to give 

 promise of ability to carry on research work. 



