EXCRETION 67 



Accessory functions of the Malpighian tubes 



Reaumur observed that the lemon yellow powder used by the larva 

 of Malacosoma neustria to cover its cocoon is a product of the Mal- 

 pighian tubes. Such products are used by other Lepidoptera: Leu- 

 coma salicis, Eriogaster lanestris, and so forth ; and we have already 

 seen how Cerambycidae strengthen their cells with lime from this 

 same source. The foam or cuckoo-spit produced by the larvae of 

 Cercopidae is formed out of a mucoprotein secretion from the 

 Malpighian tubes. And in the larvae of such widely separated insects 

 as the beetles Phytonomus (Curculionidae), Lebia (Carabidae), &c, 

 and the larvae of Neuroptera (Chrysopa, Sisyra, &c.) a part of the 

 Malpighian tube is transformed into a silk gland used, among other 

 purposes, for spinning the cocoon. 



BIBLIOGRAPHY 



craig, r. Ann. Rev. Entom., 5, (1960), 53-68 (excretion in insects: review) 

 cromartie, r. I. t. Ann. Rev. Entom., 4, (1959) 59-76 (insect pigments: 



review) 

 shaw 7 , J. and stobbart, r. h. Physiology oflnsecta, III (Morris Rockstein, 



Ed.) Academic Press, New York, 1964, 190-258 (excretion: salt and 



water balance) 

 wigglesworth, v. b. The Principles of Insect Physiology 6th Edn., 1965 



496-532 (excretion) 



