Insects : their life-histories and habits . o o. pq p» © THE PROBLEM OF DEFENCE 169 its dual function. But in the unsexed or worker classesof social species it has become a weapon pure and , the sting of a worker hive-bee consists of a groovedand pointed shaft along which slide a pair of many-barbeddarts. Externally, there are two feelers or palpi, whichare used to ascertain the most vulnerable point of first thrust is administered by the shaft, which servesto open a wound and to guide the darts. The latter thenstrike alternately with a rapid, plunging movement, whilet
Insects : their life-histories and habits . o o. pq p» © THE PROBLEM OF DEFENCE 169 its dual function. But in the unsexed or worker classesof social species it has become a weapon pure and , the sting of a worker hive-bee consists of a groovedand pointed shaft along which slide a pair of many-barbeddarts. Externally, there are two feelers or palpi, whichare used to ascertain the most vulnerable point of first thrust is administered by the shaft, which servesto open a wound and to guide the darts. The latter thenstrike alternately with a rapid, plunging movement, whilethe poison is pumped down from a chamber at the baseof the shaft. Two glands, one acid and one alkaline,minister to this deadly flow; for while the combined liquidis always acid, an alkaline admixture appears to be neces-sary to render the poison lethal. It is said that in insects,such as digger-wasps, which merely paralyse their prey,the alkaline glands are functionless or abortive. More-over, in these insects, and in most other stinging Hyme
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectinsects, bookyear1913
