'274: Clie inotropic Responses of /if sects 



deposited therein. Slomoxrjs calcitrans was also induced to oviposit on 

 cotton wool soaked with valerianic acid — a substance occurring in 

 decaying vegetable refuse. Howlett further adds that both valerianic 

 and butyric acids have a similar attraction for an Ortalid fly of the genus 

 Ulidia ( in India. H. H. P. and H. C. Severin (1913-15, 1918) have made 

 a series of studies on the attraction of kerosene for the Mediterranean 

 fruit fly, Ceraiitis capilata. Enormous numbers of this species have been 

 trapped by the agency of kerosene in various parts of the world, but the 

 number of females attracted is negligible. This species is also attracted 

 by crude petroleum, naphtha distillate, gasolene, etc., all mineral oils that 

 do not normally occur in the environment of the species. Chatter] ee 

 (1915) in India has discovered that kusum oil (oil from Schleicheria 

 trijuga) has a marked attraction for both sexes of the Coreid bug 

 Serinetha augur Fabr., and also for the nymphs in all stages. Dean (1915) 

 has discussed the value of poisoned bran mash flavoured with orange 

 or lemon juice and distributed over areas infested with grasshoppers, 

 army worms, cut worms, etc. In each case the chemotropic value of the 

 mixture was greatly enhanced by the addition of orange or lemon. 

 According to Simpson (1918) tsetse flies are attracted by oil of cloves, 

 essence of orange and essence of lemon. In Queensland, Jarvis (1916) 

 has found that the cane beetle (Lepidiofa alhohirta) is not influenced by 

 the oils of" plants allied to its food plant, but is attracted by cajeput oil, 

 acetic acid, carbolic acid, nitrobenzene, and especially oil of almonds. 

 We have, therefore, numerous instances of responses towards substances 

 which do not occur in the normal surroundings of an insect. 



The chemotropic responses of the house-fly have been more exten- 

 sively investigated than those of any other insect. Thus Morrill in 1914 

 conducted a series of experiments with a variety of substances some of 

 them of great chemical complexity, and varying very much in their 

 chemotropic properties. Among others vinegar and beer (under certain 

 conditions) were both found to be markedly attractive ; formalin varied 

 exceedingly. Commercial alcohol (95 per cent.) 1 pint, and water 20 pints, 

 was found to be more attractive after the addition of sugar. The ad- 

 dition of bread to alcohol and alcohol mixtures increased their attractive 

 properties, and also those of various other substances. Commercial 

 dried blood, moistened with water, was found to have an attractive value 

 greater than fresh and decomposed meat and flsh. Cane syrup, and sugar 

 and water, were found to have relatively low attractive values when 

 user! without other tnaterials. Buck (1915) conducted somewliat similar 

 experiments and found that not less than 3 j)or cent, nor more than 8 per 



