Vol. III. No. 29. 



JULY ISC8. 



^ IRISH QARDEINIING 



A Monthly Educational Journal devoted to 

 the Advancement of Horticulture in Ireland 



C 



The Gooseberry Saw-fly. 



By Professor GEORGE H. CARPENTER, B.Sc. 



OM PLAINTS have been received from of Hymenoptem in having- no constricted 

 many parts of the country during the last waist'; the base of the abdomen is broad, 

 few weeks about the ravag-es of the cater- so that the body appears "parallel sided.'' 



pillars of this insect on 

 g-ooseberry and currant 

 bushes. A short ac- 

 count of its life-history 

 may, therefore, be of 

 interest to readers of 

 Irish Gardening. 



With most common 

 insects it happens that 

 the perfect winged form 

 {imago) is much more 

 familiar than the larva. 

 Probably, however, 

 there are many who 

 know, too well, the 

 black - spotted cater- 

 pillars that feed on 

 gooseberry leaves, 

 but who have never 

 seen the parent-fly. 

 It is a saw-fly (Ne- 

 matus ritesii by name) 

 belonging to the order 

 of the Hymenoptem ; 

 this order includes 

 gall-flies, ichneumon 

 flies, ants, wasps, 

 and bees— in sec t s 

 distinguished by the 

 presence of two pairs 

 of membranous wings 

 not covered with 

 scales like the wings 

 ofmoths. Now, most 

 Hymenopfera are well 

 known for their ex- 

 cessively slender 

 waist between thorax 

 and abdomen ; the ' 



. ^ I 



P/wto /'!/] [T. Price: 



Branch of Red Currant denuded of leaves by 

 Caterpillars of the Gooseberry Saw-fly. 



The Photograph shows the Winged Fly, the Caterpillar, and the 

 Cocoon. 



IVenuifus ritesii is a 

 small, pretty fly about 

 yi inch long and meas- 

 uring y2 inch across the 

 wings when they are 

 spread out. The fe- 

 male has a blackish 

 head and thorax and 

 a bright yellow abdo- 

 men ; in the male the 

 abdomen is darker. 

 The flies first appear 

 in April or May, and 

 the female lays a num- 

 ber of eggs below the 

 surface of a single 

 gooseberry or currant 

 leaf, placing them near 

 the ribs of the leaf 

 and fastening them 

 with a sticky secretion. 

 In about a week the 

 tiny caterpillars are 

 hatched from these 

 eggs. They are pale- 

 green, only j-2 inch 

 long, and for a short 

 time they all feed be- 

 neath the leaf on which 

 they were hatched. 

 As a result, the leaf 

 becomes pierced with 

 a large number of very 

 small holes, and, when 

 viewed from above, it 

 looks as if perforated 

 by numerous pin- 

 pricks. Now is the 



wasp-waist " has be- time for the watchful gardener, observing this 

 come proverbial. But the family of saw-flies state of affairs, to pick all such leaves and 

 {Tenthredinidce) diff"er from the great majority burn them with the young caterpillars. 



