The histochemical effect of topical application of 20-Hydroxy Ecdysone (20-HE) to nymphal Hyalomma (H.) dromedarii stimulated a marked increase in the content of proteins, lipids and carbohydrates in the secretory cells of the secretory lobe of the foveal gland of female Hyalomma (H.) dromedarii in unfed, semi-fed females and fully fed-females. The histochemical changes of content of proteins, lipids and carbohydrates are studied in females treated with 20-Hydroxy Ecdysone and compared to untreated females at different physiological conditions.