2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 97 



and not mandibles. Berlese's " Gli Insetti " (1910) contains some in- 

 formation on the maxillary musculature. Tillyard (1923) demon- 

 strated that the maxillary lobes forming the proboscis are probably 

 the galeae. Weber (1924) has contributed to our knowledge of the 

 occipital area and the cervix of certain species. Snodgrass (1935) de- 

 scribed the sucking pump of a sphingid. 



This study was made possible only through the invaluable instruc- 

 tion and encouragement of R. E. Snodgrass, of the Bureau of Ento- 

 mology and Plant Quarantine of the United States Department of 

 Agriculture, and I am therefore especially indebted to him. I am also 

 indebted to Dr. T. J. Headlee, of Rutgers University, and to Dr. E. N. 

 Cory, of the University of Maryland, for their cooperation while at 

 their respective institutions. I also appreciate the aid of Dr. A. B. 

 Klots, of the City College of New York, in determining microlepi- 

 doptera. This study formed the larger part of a thesis submitted in 

 partial fulfillment of the requirements for the degree of Doctor of 

 Philosophy at Rutgers University. 



I. GENERAL STRUCTURE OF THE HEAD AND MOUTHPARTS 



The cranium of the lepidopterous head is a relatively simple struc- 

 ture showing very few sutures. The clypeus forms an elongate an- 

 terior area and is not marked off from the frons. A suture extends 

 on each side from the invagination of the anterior arm of the tentorium 

 to the antenna fossa in the butterflies and most of the higher moths, 

 but is usually absent in the more generalized groups. Whether this 

 suture is a true frontal suture is questionable, for, as will be seen later, 

 its internal ridge seems to have been developed secondarily for the 

 purpose of bracing the cranium against the pull of the antenna muscles, 

 which originate on the anterior arms of the tentorium. The internal 

 ridge of this suture will be called the antennal ridge (fig. i. A, AR). 

 The parietals are large, and in the higher Lepidoptera their size is 

 further increased by the great development of the compound eyes. 

 The ventral and anterior ends of each parietal are recurved mesally, 

 thereby providing between them a recess for the maxillae and the 

 labium (fig. 12, B). Posteriorly and dorsally, the parietals merge 

 with the occiput, there being no limiting suture. The postoccipital 

 suture has a well-developed internal ridge and is itself usually evident 

 externally. It limits the dorsal part of the posterior edge of the occi- 

 put, the ventral part being limited by the much lengthened hypostomal 

 sutures. The invaginations of the posterior arms of the tentorium are 

 located in the ends of the postoccipital suture, and since most of each 

 hypostomal suture lies in the same dorsoventral line as the lateral part 



