10 B. C. ENTOJIOLOGICAL SOCIETY 



LIFE-HISTORY 

 The larvae were first taken on April 28, 1917, on Vancouver Island, 

 and were observed to be feeding- on the leaves of the false bugbane, 

 Trautvetteria grandis (Ranunculaceae). The food-plant generally affects 

 damp and well-shaded habitats, and in this particular instance it was 

 growing in great luxuriance in a rich woodland timbered by lofty cedars 

 and spreading, large-leaved maples. At the time of first collection, the 

 larvae appeared to be in the penultimate stage of their development. 

 They were reared to maturity and the adults were obtained, both sexes, 

 from the resulting pupae. 



Egg Stage. Individual plants of Trautvetteria grandis were potted, 

 and one each placed in special breeding cages. As the adults emerged 

 from the pupal skins (May 15-30), they were transferred to the breeding 

 cages. Copulation was undertaken soon after emergence, and the female 

 deposited her elongate, glistening, white eggs along the margin of the 

 leaves, generally on the under-surface. Under natural conditions the 

 eggs were found to be invariably laid on the lower surface, but in the 

 more confined area of the breeding cages, eggs were also deposited on the 

 margin of the upper leaf-surface. 



The female ovipositor is unicjue among Tipulidae, and consists of 

 (1) a pair of double-bladed cutting valves; (2) an unpaired, upper, 

 bifurcated valve; and (3) an unpaired, lower, plough-share valve. 

 Each one of the cutting valves bears an inner, serrate-edged blade, and 

 an outer, unserrated blade. It is their function to slit the epiderm of 

 the leaf whilst the plough-share valve guides the egg into the resulting 

 slit. The bifurcated valve apparently serves to keep the leaf in position 

 during the operation of ovipositing, since the leaf-margin is held securely 

 between this valve and the cutting valves. 



The eggs are not wholly hidden. They are generally laid in close, 

 parellel series, lending to the leaf-margin a characteristic, beaded appear- 

 ance. The period of incubation occupies about two weeks. 



Larval Stage. The first stage larvae are a semi-translucent greyish- 

 white, and measure 1.19 mm. long and 0.37 mm. broad soon after they 

 emerge from the egg. The segmental tubercles and pro-legs so char- 

 acteristic of the mature larvae, are readily distinguishable although they 

 are as yet not well developed. The black head-capsule stands out in 

 decided contrast to the semi-transparent liod)'. 



The young larvae are very sluggish and are not readily disturbed 

 when feeding. The mandibles are very firmly embedded in the leaf- 

 tissue. Their movements are very characteristic and can be most aptly 

 compared with those of the "measuring worms" or "looper-caterpillars" 

 (CTeometridae). 



