384 



PHYLUM ARTHROPODA 



duct the globular spermatheca is associated. In connection with it 

 there is a gland corresponding to the mucus gland of the male. The 

 oviduct terminates in a copulatory pouch. 



Previous to laying, the eggs are fertilised by sperms set free from 

 the spermatheca. In the case of drone eggs, this liberation of sper- 

 matozoa does not take place, and the eggs in consequence are partheno- 

 genetic. Queens which have never mated, or which have exhausted 

 their stock of male elements, habitually lay drone eggs, but those which 

 are laying abundant fertilised eggs at times also lay unfertilised eggs. 

 This withholding of spermatozoa is said to be " voluntary," and 

 related to the needs of the colony, but the physiological reason is 

 unknown. 



The workers possess female organs similar in type to those of the 

 queen, but of an extremely rudimentary nature. 



The eggs are laid singly in the cells of the comb, at the rate of about 

 two per minute, for weeks together. They are of the usual insect 

 type. According to the size of the cell in which it is deposited, and 

 the food with which it is furnished, the fertilised ovum develops into 

 a worker or into a queen. The development takes place within the 

 cell, and includes a complete metamorphosis. 



Classification of Insects 



I. Primitive wingless insects, Apterygota or Aptera, including 

 Thysanura, e.g. Machilis, Campodea, Lepisma ; Collembola, 

 Springtails, e.g. Podura, Smynthurus. 



II. Winged insects, Pterygota (in some degenerate forms the wings 

 have been lost). 



A. With mouth-parts usually adapted throughout life for biting 



(Menognathous), with no metamorphosis (Ametabolic) or 

 with incomplete metamorphosis (HemimetaboUc). 



e.g. Orthoptera (cockroach, locust, cricket, etc.) ; 

 Corrodentia (Termites, bird-lice) ; Odonata 

 (Dragon-flies) ; Ephemerida (May-fiies) ; and 

 Dermaptera (Earwigs). 



B. With mouth-parts adapted in the main as suctorial organs 



(Menorhynchous), usually with no metamorphosis 



(Ametabolic). 



e.g. Rhynchota or Hemiptera, e.g. Phylloxera, aphides, 

 coccus insects ; Cicadas ; bugs ; water-scor- 

 pions, lice. 



C. With complete metamorphosis (Holometabolic), with 



mouth-parts always adapted for biting (Menognathous), 

 or adapted at first for biting and afterwards for sucking 

 (Metagnathous). 



e.g. Coleoptera (beetles) ; Diptera (two-winged flies) ; 

 Lepidoptera (butterflies and moths) ; Hymen- 

 optera (ants, bees, and wasps). 



