March 19, 1874. I 



JOURNAL OP HORTICULTURE AND COTTAGE GARDENER, 



237 



owing to this many of tlie species are rare. Hairy caterpillars 

 do not always find their coating a protection ; those of the 

 " Tigers " and the " Daggers " (Arctia and Acronycta) die-oS 

 through the attacks of these parasites, the long ovipositor of 

 the females enabling them to reach and even to puncture the 

 skin of the larva. 



There is something so striking about the "cut" of an 

 Ichneumon fly, that if wo have once seen one and well ex- 

 amined it we never fail to recognise these insects thereafter. 

 Their form, it has been well said, combines lightness and 

 strength. The wings are usually of good size, with clearly 

 marked veins ; the head is small, and has a mobile look about 

 it ; the abdomen, nearly always long and slender, is attached 

 only by a small thread to the end of the thorax, and provided 

 with an ovipositor, sometimes retractile, and at others extend- 

 ing to a greater length than that of the abdomen — adapted, 

 in fact, to the habits of the species, for some of the Ichneu- 

 mons manage to deposit their eggs by the help of the long 

 ovipositor upon hapless insects they have never seen, such as 

 the larva of the Tortrix moth in his leafy investiture, the 

 snug tenant of the gall, or, perhaps, the grub of a beetle 

 hidden away in decayed wood. What is, perhaps, more 

 singular than all is that one or two Ichneumon flies actually 

 skim the water of pools and streams, and seize an opportunity 

 to puncture the bodies of aquatic larva) or pupa;. 



Species of Ophion.^^ 



Though in popular phrase we speak of caterpillars as 

 " stung " that have fallen victims to the Ichneumons, they 

 inflict no wounds that are poisonous ; the only object of their 

 punctures is the deposition of eggs. But several species 

 simply deposit their eggs on the skin of the caterpillar, and 

 therefore the females are not in that case armed with a piercer 

 or with lancets as are the Pimplas. Flies of the genus Ophion, 

 such as the well-known species (Ophion Vinulfe ?) that attacks 

 the caterpillars of the Puss Moth, secure the eggs to the skin 

 by such an adhesive fluid that they cannot be pulled off the 

 caterpillar without wounding it. The experiment has, how- 

 ever, been tried successfully of carefully nipping the eggs, and 

 so destroying the germ of life within. Kirby observed some 

 of these eggs stood upon the backs of larva; by short foot- 

 stalks. It is rather extraordinary that when these parasites 

 are feeding externally, as often happens with the Ophions, 

 they manage to retain their position in spite of the moulting 

 of the caterpillar, and their period of maturity generally 

 agrees with that of their living food. When the caterpillar 

 has made its cocoon, or occasionally before, its enemies quit 

 their hold and form their own cocoons. 



The Yellow Ophion (0. luteum), is a spring and summer 

 species, and it is exceedingly partial to artificial light, entering 

 rooms in the evening, when it looks much larger than it really 

 is, as seen reflected against the ceiling, and its aspect leads 

 persons to suppose that it is a " vicious " insect. Really it is 

 useful to the horticulturist, nor should specimens of it be 

 needlessly killed. The claws of this fly seen by a moderate 

 magnifying power have a pretty appearance. A few of the 

 Ophions have a short sickle-like auger, by means of which 

 they cut a place for the egg they deposit. The males of these 

 species resort to flowers, but they are less frequently seen than 

 their consorts. 



Prof. Westwood has described, with his usual accuracy, the 

 proceedings of a species of Pimpla engaged in the pursuit of 

 larvEe encased in wood. The insect had seemingly made several 

 cautious insertions of its ovipositor until it succeeded in hitting 

 upon the exact spot. Only the central borer was thrust into 

 the wood, the outer portions being curved, and pressed against 

 the wood as if to give the power of a lever. The abdomen was 

 also worked backwards and forwards at intervals, giving a 



' From Figuier's " Insect World.'' 



" bradawl kind of motion." Another entomologist teUs us that 

 ho saw a Pimpla plunge all its lancets into the object it was 

 attacking. Some of these long-tailed Ichneumons have been 

 discovered with the ovipositor so far entangled that they have 

 been unable to get free and have died in their struggles. There 

 is a species of Ophion which has a fancy for variety in its food, 

 and hunts up the larva; of a Pimpla which has previously 

 attacked the nest of a wUd bee. Thus we have a parasite upon 

 a parasite. 



Rhyssa persuasoria is a useful insect in plantations, as it 

 seeks out the larva; of Sirex, usually of S. juvencus, which is 

 in some seasons more than sufficiently plentiful, and injurious 

 to several species of Fir, in the wood of which the larva drives 

 long tunnels. This fly is another of the three-tailed Ichneu- 

 mons, and it may be seen traversing the bark of a tree, and 

 ascertaining by the antenna; where the larva is hidden, in 



Species of Pimpla.* 



which it seeks to deposit eggs. It is a moot point how the 

 antenna; of the insect help it to discover the object. Whether 

 the touch, or the sense of smell or hearing conveys tho im- 

 pression we cannot say, but it is promptly acted on. This is 

 one of the few instances where the parasite is as large or larger 

 than the animal attacked, thus interrupting the harmony of 

 gradation. Here we have a beetle larva falUng a prey to Ich- 

 neumons, and we shall ere long possibly discover many ex- 

 amples of a similar kind. At present the Ichneumouidse are 

 best known to us as the occasional foes of others of their own 

 order, and the constant enemies of caterpillars of all propor- 

 tions, from the giant Death's-head down to the tiny silvery 

 leaf-miner. — J. R. S. C. 



GRAPE VINE CULTURE FOE SMALL GARDENS 



No. 2. 

 When the soil is not sufficiently fertile for the Vines it may 

 almost always be made so by mixing with it some old manure 

 that is thoroughly rotten, and some gritty matter, such as 

 road-scrapings, mortar rubbish, broken bricks, or, in fact, any 

 hard materials that are brought to a tolerable degree of fine- 

 ness, in order to prevent the border from settling down into a 

 close sodden mass. The proportions should be two parts of 

 SOU, one of manure, and one of grit, more or less according to 

 the actual condition of the soil. A little charcoal broken to 

 the size of nuts may be added with advantage. This simple 

 mixture should, if possible, be made a few months before it is 

 required, thrown up in a heap or long ridge, and turned fre- 

 quently whenever it is dry enough, so as to render it thoroughly 

 sweet and mellow by the action of the air. Especial care must 

 be taken neither to stir it or take it to the vinery while it is very 



