28 



Buds do not appear to be fond of these larvae, indeed there is reason 

 to beheve that they are distasteful to them and thus protected 

 But they have a very deadly enemy in a tmy four- winged fly You 

 have no doubt noticed under the coping of walls and on fences near 

 cabbage gardens m autumn, especially in seasons when the butterfly 

 has been unusually abundant, the remains of a larva surrounded by 

 a bunch of little pale yellow cocoons. These are the work of this 

 fly, a Hymenopteron known by the name of Apautdes „ln,>,eratns L 

 ihe parent fly stabs the young lepidopterous larva with'its ovipos tor 

 and pushes its eggs under the larval skin, these shortly hatcfh and 



onnhi^ ™ ".i "P. '"''^^' '^" lepidopterous larva, but without 

 touching any vital part unt.l it is full-fed and has just hun<. itself 



Z\T\ ""uT"''-- .^''' V""''^' "^"^ "'^° ^^1^-^^^^ ^t this tim:, they 

 then kill their victim and eat their way out through its skin and 

 ep.n their cocoons all around it. That we owe a very great deal to 

 this little parasitic fly in keeping down the attacks of the butterflv 

 larvae on our cabbages will be gathered from the fact that in 1917 

 a year when the butterfly was exceedingly abundant, from many' 

 thousands of larvae collected in various parts of the country 

 on y between 1 and 2 per cent reached maturity, all the others bei/^ 

 killed by the attacks of the fly. ° 



No other butterfly can be regarded as anything like so serious a 

 pest. P. rapae L. (Small Garden White), it is true, may occasion- 

 ally strip our Tropeolums of their leaves,' but even 'so the damage 

 s of no material importance and it seldom causes senous trouble 

 in tne kitcben garden. 



Note.— Since this paper was in manuscript one of the rare 

 occasions when P. rapae was really harmful occurred. The 

 imagines of the summer emergence were far more abundant than 

 sLial and in the autumn the cabbage plants in our gardens were 

 badly eaten by larvae, an examination of which showed that from 

 eighty to ninety per cent, of them were P. rapae. 



The Sphinges although of great size are not a very harmful -roun 

 At rare intervals one hears that potato plants are being stripped 

 by Mandnca atmpo,, L. (Death's Head Hawk Moth), but in such 

 cases it IS generally more fright on the part of the observer at the 

 size of the enemy than any real harm that it does, for the species 

 never occurs in dangerous numbers in this country 



As illustrating how easily people may be frightened by size, some 

 years ag^ a frantic letter was received from a large apple grower in 

 Herefordshire to the effect that some huge caterpillars had 

 descended upon his orchards like a flock of locusts and were 

 devouring all his trees. Naturally we felt interested and wrote off 

 at once asking him to send us a good sample of the caterpillars so 

 that when we knew what they were we might be able to help him 



