1. The relationship between chemical constitution and toxicity to wireworms of organic compounds is found to be of a twofold nature.2. The general effect of a group of compounds of the same type is directly determined by the chemical constitution of the type. The particular effects of individual members of the groups are limited by their physical properties such as volatility etc., which may be regarded as indirect consequences of their chemical constitution.3. The aromatic hydrocarbons and halides are on the whole more toxic than the aliphatic hydrocarbons and halides. The groups that influence toxicity most when introduced singly into the benzene ring are in order of importance the methylamido (most effective), dimethylamido, hydroxy, nitro, amido, iodine, bromine, chlorine, methyl groups (least effective). But this order is modified in presence of another group; thus when there is a CH3 already present in the ring the order becomes chlorine (side chain), amido, hydroxy, chlorine (ring), methyl. Chlorine and hydroxy groups together give rise to highly poisonous substances considerably more effective than where present separately. The association of chlorine and nitro groups in chloropicrin gives rise to one of the most toxic substances tested. Methyl groups substituted in the amido group of aniline increase toxicity more than if substituted in the ring.
A QRIOTELI rSPUTATOR, L.OF the life history of this species as distinct from that of other memben of the genus. not much is as yet known. Bollar in 1837 referred to the larva as feeding on lettiices and describes it as being "light yellow, from six to seven lines long, of the thickness of a pigeon's quill." Curtis(5) (p. 167) and other writers of the nineteenth century seem to have taken their accounts of the species from Kollar, whose details are so very meagre. ddrianov~), however, as has already been mentioned, obtained the ova and young larvae in Russia in 1914. But he does not appear to have grown the larvae for more than a year and his description of the experiments he made provides no means of distinguishing this larva from otliers of the same genus.Mv own attempts to breed this species from the egg have, from one cause or another, not been very fortunate, though I have obtained ova from my breeding pots in three separate years. The longest-lived brood did not quite survive two years (1916-19181, but from it a few points have at least emerged; firstly, that the rate of growth of the larva within the time named was almost the mme as that of A. obscurrus of the same age, and secondly particular features of the structure have been observed, providing the link connecting the young larvae with older larvae which were taken in the field and from which beetles were bred.I n regard to the first point, only two larvae were obtained after the second winter, but if these can be considered to be of normal size, as is probable, and if their future rate of growtk would have corresponded with the past rate, then it appears that there is but little difference in 1 A p n t has bean received for publication of thia paper.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.