7 

 a maximum spectral sensitivity at 520 nm obtained from electroretinograms withAe. 



aegypti [4,10]. 



In adults, the lateral ocelli degenerate and compound eyes are present. The 



dorsal ocelli are absent. The compound eyes consist of ommatidia. Each 



ommatidium consists of a diotropic apparatus (cornea, lens, and four cone cells for 



light collection) and a retinal cell layer [4]. For Ae. aegypti, the interommatidial 



angle is 6.2°; this angle is much greater than, for example, for houseflies. Due to 



the greater angle, theAe. aegypti has relatively poor visual resolution and poor acuity 



[10]. However, mosquito vision does exhibit a high overall sensitivity to light [9, 10]. 



Mosquito Repellents 



Almost all compounds found to be chemical attractants (kairomones) for a 

 specific species of mosquito are chemical repellents (allomones) for other specific 

 species. Work conducted using l-octen-3-ol (see section on Emanations from 

 animals including man) has shown that this is a very promising attractant. Octenol, 

 in combination with carbon dioxide, attracted some of the 35 species in a field study 

 by Kline [11]. However, this compound acted as an allomone in the case of Cidiseta 

 melanura. 



The grooved pegs on Ae. aegypti respond to lactic acid and are inhibited by 

 the popular repellent diethyl-meta-toluamide (deet) [3,6,12]. Although oxalic acid 

 itself is not an attractant (i.e. the lactic acid excitatory neuron does not respond), it 

 does interfere or inhibit lactic acid response [12]. This interference is also the basis 



