258 I^P"'- 
" This year, whilst examining, in a kitchen-garden, the onions in seed, I was 
struck by the appearance of a disease ; several stems were completely stripped, 
others bore an umbel which was so slightly attached that the least touch brought 
off all the flower-stalks at once. These flower-stalks had been gnawed at their 
base, and their union with the common stem was transformed into a flour-like mass. 
Here was evidently the work of an insect larva, and not a disease of the plant. On 
blowing uiDon this dust I immediately discovered a quantity of small larvaa, which 
seemed at the first glance as though they belonged to some Dipterous insect, but 
on examining them more closely I perceived that they were small Lepidopterous 
larvae. These larvae produced Boslerstammia assectella. 
" The larva is of a transparent dirty yellow, like old pieces of polished bone ; it 
bears a little shield on the second segment, and has two rows of little black hair- 
bearing dots, hardly perceptible to the naked eye ; it is slightly attenuated in front, 
and during repose swollen posteriorly. It feeds gregariously in the flower stems of 
the onion, Allium ce%m, not making separate galleries, and not ejecting its excre- 
ment nor collecting it together. The larvae are full-grown towards the commence- 
ment of September, and then quit the stem, some perforating the sides of it, but 
the greater number passing out at the base of the umbel ; the pupae are placed 
singly, some amongst the flower-stalks, but the greater number of the larvae descend 
the stem and disperse themselves over the ground. 
" The chrysalis is enclosed in a very pretty net-work cocoon, like very close tulle, 
and tolerably firm. At the end of three weeks the imago appears ; it is sufficiently 
well known and I need not therefore describe it. It hybernates, and the following 
spring the female deposits her eggs on the growing flowering- stems of the onion. 
Assectella must be included in the list of insects injurious to horticulture, for 
although it does not actually damage the plant in which it Hves, it hinders, or at 
any rate diminishes, the production of seeds." 
Under the name of Tinea Vigeliella of Duponchel, Colonel Goureau in his 
interesting " Insectes nuisibles," has given at p. 204, a history of "lateignedu 
poireau et de I'ognon," (which is in truth A. assectella), from which I quote the 
following : — " We sometimes perceive at the end of September or the beginning of 
October, that plants of leek are attacked by small larvae which have taken up their 
abodes in the thick leaves of that vegetable. They excavate longitudinal galleries 
either straight or tortuous, which only occupy half the thickness of the leaf, and 
they devour all the substance which they excavate. They do not always remain in 
the same gallery, and move readily from place to place. They pierce the leaf to 
reach the other side of it, where they form new galleries, or they proceed to another 
leaf which they gnaw in a similar manner. When these larvae are numerous, as 
happens some years, they soon destroy a whole row of leeks, or even all in 
the garden. They eat almost incessantly and are soon full fed ; this happens 
towards the 6th of October The perfect insects appear about the 
17th November ; but the entire brood does not then come out ; some pass the 
winter in the pupa state, and do not take wing till the following spring, when in the 
months of April or May, they deposit their eggs on the leaves of young onions, 
producing a spring brood which attacks the onions as the autumn brood has 
attacked the leeks." 
