affecting Carrots and Parsnips. 
187 
beneath : ovipositor black ; oviduct chestnut-colour, scarcely so 
lonq: as the body : length 2 to 3^ lines. 
This parasite is also often ct)ncealed in its maggot state in the 
caterpillars of D. Daucella and other kindred species : both 
sexes frequent the parsnip when in flow^er, the beginning of July, 
and have been taken in the market-gardens round London. 
I am not aware whether the caterpillars of the Deprcssarice 
ever do much mischief in England, but if they have not yet been 
abundant, it is in all probability owing to the comparatively small 
quantity of carrot and parsnip seeds grown in this country, and 
this will be no security against their appearance at some future 
period ; for owing to the rapid intercourse between distant 
countries, from peculiar atmospheric changes, and from unknown 
causes, certain species of insects appear and disappear in almost a 
mysterious way ; but it is incontrovertible that if a vegetable be 
cultivated to any extent in the open ground, its enemies will 
not be long before they come to claim their portion (not unfre- 
quently the lion's share) of the produce. As these subjects are 
more generally studied and better understood, their importance 
and value will become more evident. Even the remedies sug- 
gested and the hints thrown out, if they be not immediately acted 
upon, may some day fall on good ground and bring forth fruit 
abundantly to the advantage of the farmer and the public. 
The vast per centage of our vegetable produce which is con' 
sumed, not by man, but by insects, those almost unobserved 
visitors — is really incredible. In a wild state of nature their 
services are most important in reducing the superabundance of 
rank vegetation ; they are not only the scavengers, but the 
labourers, whose unceasing industry thins the crops and keeps 
trees, shrubs, and flowers from smothering one another with their 
luxuriance : at the same time they are manuring the soil and 
rendering it more productive and more speedily applicable to the 
wants of the human species: but when the soil is subjected to the 
skill and industry of man and the produce is to be the reward 
of his anxiety and labour, the farmer and gardener consider 
naturally enough, that the services of a great many insects might 
be dispensed with, advantageously to themselves and no doubt 
with benefit to the public. 
Before attempting to wrestle with such insidious enemies three 
things are most essential — knowledge, industry, and perseverance. 
Wanting the first, we may do more harm than good, by destroying 
our friends instead of our enemies: without industry, the economy 
of insects can never be attained ; and if we have not a great share 
of perseverance, the best conceived remedies may prove futile. 
" Practice with Science " in every department of agriculture must 
lead to useful results ; and I trust amongst others, that the science 
